diff --git a/backend/report.html b/backend/report.html
index 1b97bae..ef617d6 100644
--- a/backend/report.html
+++ b/backend/report.html
@@ -328,7 +328,7 @@ div.media {
   </head>
   <body>
     <h1 id="title">Backend Testing Report</h1>
-    <p>Report generated on 24-Jan-2025 at 16:01:23 by <a href="https://pypi.python.org/pypi/pytest-html">pytest-html</a>
+    <p>Report generated on 27-Jan-2025 at 14:23:18 by <a href="https://pypi.python.org/pypi/pytest-html">pytest-html</a>
         v4.1.1</p>
     <div id="environment-header">
       <h2>Environment</h2>
@@ -382,7 +382,7 @@ div.media {
         <h2>Summary</h2>
         <div class="additional-summary prefix">
         </div>
-        <p class="run-count">8 tests took 00:01:20.</p>
+        <p class="run-count">2 tests took 00:00:03.</p>
         <p class="filter">(Un)check the boxes to filter the results.</p>
         <div class="summary__reload">
           <div class="summary__reload__button hidden" onclick="location.reload()">
@@ -392,10 +392,10 @@ div.media {
         <div class="summary__spacer"></div>
         <div class="controls">
           <div class="filters">
-            <input checked="true" class="filter" name="filter_checkbox" type="checkbox" data-test-result="failed" />
-            <span class="failed">3 Failed,</span>
+            <input checked="true" class="filter" name="filter_checkbox" type="checkbox" data-test-result="failed" disabled/>
+            <span class="failed">0 Failed,</span>
             <input checked="true" class="filter" name="filter_checkbox" type="checkbox" data-test-result="passed" />
-            <span class="passed">5 Passed,</span>
+            <span class="passed">2 Passed,</span>
             <input checked="true" class="filter" name="filter_checkbox" type="checkbox" data-test-result="skipped" disabled/>
             <span class="skipped">0 Skipped,</span>
             <input checked="true" class="filter" name="filter_checkbox" type="checkbox" data-test-result="xfailed" disabled/>
@@ -432,7 +432,7 @@ div.media {
     </table>
   </body>
   <footer>
-    <div id="data-container" data-jsonblob="{&#34;environment&#34;: {&#34;Python&#34;: &#34;3.12.3&#34;, &#34;Platform&#34;: &#34;Linux-6.8.0-51-generic-x86_64-with-glibc2.39&#34;, &#34;Packages&#34;: {&#34;pytest&#34;: &#34;8.3.4&#34;, &#34;pluggy&#34;: &#34;1.5.0&#34;}, &#34;Plugins&#34;: {&#34;html&#34;: &#34;4.1.1&#34;, &#34;anyio&#34;: &#34;4.8.0&#34;, &#34;metadata&#34;: &#34;3.1.1&#34;}}, &#34;tests&#34;: {&#34;src/tests/test_main.py::test_turckheim&#34;: [{&#34;extras&#34;: [], &#34;result&#34;: &#34;Passed&#34;, &#34;testId&#34;: &#34;src/tests/test_main.py::test_turckheim&#34;, &#34;resultsTableRow&#34;: [&#34;&lt;td class=\&#34;col-result\&#34;&gt;Passed&lt;/td&gt;&#34;, &#34;&lt;td class=\&#34;col-testId\&#34;&gt;src/tests/test_main.py::test_turckheim&lt;/td&gt;&#34;, &#34;&lt;td&gt;start (0 | 5) - 5 - Porte de France (157 | 5) - 5 - finish (0 | 5) - 0&lt;/td&gt;&#34;, &#34;&lt;td&gt;20 min&lt;/td&gt;&#34;, &#34;&lt;td&gt;20 min&lt;/td&gt;&#34;, &#34;&lt;td class=\&#34;col-duration\&#34;&gt;110 ms&lt;/td&gt;&#34;, &#34;&lt;td class=\&#34;col-links\&#34;&gt;&lt;/td&gt;&#34;], &#34;log&#34;: &#34;------------------------------ Captured log call -------------------------------\nINFO     src.main:main.py:65 No end coordinates provided. Using start=end.\nINFO     src.main:main.py:97 Fetched 5 landmarks in  \t: 0.004 seconds\nINFO     src.main:main.py:122 Total computation time\t: 0.035 seconds\nINFO     src.main:main.py:127 Generated a trip of 20 minutes with 3 landmarks in 0.039 seconds.\nINFO     httpx:_client.py:1025 HTTP Request: POST http://testserver/trip/new &amp;quot;HTTP/1.1 200 OK&amp;quot;\n\n&#34;}], &#34;src/tests/test_main.py::test_bellecour&#34;: [{&#34;extras&#34;: [], &#34;result&#34;: &#34;Passed&#34;, &#34;testId&#34;: &#34;src/tests/test_main.py::test_bellecour&#34;, &#34;resultsTableRow&#34;: [&#34;&lt;td class=\&#34;col-result\&#34;&gt;Passed&lt;/td&gt;&#34;, &#34;&lt;td class=\&#34;col-testId\&#34;&gt;src/tests/test_main.py::test_bellecour&lt;/td&gt;&#34;, &#34;&lt;td&gt;start (0 | 5) - 5 - H\u00f4tel de l&#39;Europe (217 | 5) - 4 - Palais archi\u00e9piscopal (217 | 5) - 6 - \u00c9glise Saint-Georges (461 | 5) - 3 - Grande Synagogue de Lyon (217 | 5) - 10 - \u00c9glise Saint-Just (460 | 5) - 13 - Basilique Notre-Dame de Fourvi\u00e8re (281 | 5) - 5 - Site historique de Lyon (414 | 5) - 4 - Temple du Change (406 | 5) - 13 - Basilique Saint-Bonaventure (414 | 5) - 12 - finish (0 | 5) - 0&lt;/td&gt;&#34;, &#34;&lt;td&gt;125 min&lt;/td&gt;&#34;, &#34;&lt;td&gt;120 min&lt;/td&gt;&#34;, &#34;&lt;td class=\&#34;col-duration\&#34;&gt;00:00:09&lt;/td&gt;&#34;, &#34;&lt;td class=\&#34;col-links\&#34;&gt;&lt;/td&gt;&#34;], &#34;log&#34;: &#34;------------------------------ Captured log call -------------------------------\nINFO     src.main:main.py:65 No end coordinates provided. Using start=end.\nINFO     src.main:main.py:97 Fetched 182 landmarks in  \t: 0.042 seconds\nINFO     src.main:main.py:122 Total computation time\t: 8.903 seconds\nINFO     src.main:main.py:127 Generated a trip of 125 minutes with 11 landmarks in 8.945 seconds.\nINFO     httpx:_client.py:1025 HTTP Request: POST http://testserver/trip/new &amp;quot;HTTP/1.1 200 OK&amp;quot;\n\n&#34;}], &#34;src/tests/test_main.py::test_cologne&#34;: [{&#34;extras&#34;: [], &#34;result&#34;: &#34;Failed&#34;, &#34;testId&#34;: &#34;src/tests/test_main.py::test_cologne&#34;, &#34;resultsTableRow&#34;: [&#34;&lt;td class=\&#34;col-result\&#34;&gt;Failed&lt;/td&gt;&#34;, &#34;&lt;td class=\&#34;col-testId\&#34;&gt;src/tests/test_main.py::test_cologne&lt;/td&gt;&#34;, &#34;&lt;td&gt;start (0 | 5) - 2 - Excelsior Hotel Ernst (793 | 5) - 2 - St.Andreas (632 | 5) - 4 - K\u00f6lner Dom (1474 | 10) - 2 - R\u00f6misch-Germanisches Museum (901 | 60) - 5 - Gro\u00df St. Martin (582 | 5) - 9 - St. Maria im Kapitol (633 | 5) - 4 - Trinitatiskirche (604 | 5) - 11 - St. Peter (538 | 5) - 7 - Oper der Stadt K\u00f6ln (601 | 5) - 3 - Galeria (531 | 30) - 4 - St. Maria in der Kupfergasse (518 | 5) - 9 - St. Gereon (1059 | 5) - 11 - St. Ursula (529 | 5) - 10 - St. Kunibert (691 | 5) - 10 - finish (0 | 5) - 0&lt;/td&gt;&#34;, &#34;&lt;td&gt;253 min&lt;/td&gt;&#34;, &#34;&lt;td&gt;240 min&lt;/td&gt;&#34;, &#34;&lt;td class=\&#34;col-duration\&#34;&gt;00:00:53&lt;/td&gt;&#34;, &#34;&lt;td class=\&#34;col-links\&#34;&gt;&lt;/td&gt;&#34;], &#34;log&#34;: &#34;client = &amp;lt;starlette.testclient.TestClient object at 0x7b7aaac3a000&amp;gt;\nrequest = &amp;lt;FixtureRequest for &amp;lt;Function test_cologne&amp;gt;&amp;gt;\n\n    def test_cologne(client, request) :   # pylint: disable=redefined-outer-name\n        &amp;quot;&amp;quot;&amp;quot;\n        Test n\u00b02 : Custom test in Lyon centre to ensure proper decision making in crowded area.\n    \n        Args:\n            client:\n            request:\n        &amp;quot;&amp;quot;&amp;quot;\n        start_time = time.time()  # Start timer\n        duration_minutes = 240\n    \n        response = client.post(\n            &amp;quot;/trip/new&amp;quot;,\n            json={\n                &amp;quot;preferences&amp;quot;: {&amp;quot;sightseeing&amp;quot;: {&amp;quot;type&amp;quot;: &amp;quot;sightseeing&amp;quot;, &amp;quot;score&amp;quot;: 5},\n                                &amp;quot;nature&amp;quot;: {&amp;quot;type&amp;quot;: &amp;quot;nature&amp;quot;, &amp;quot;score&amp;quot;: 5},\n                                &amp;quot;shopping&amp;quot;: {&amp;quot;type&amp;quot;: &amp;quot;shopping&amp;quot;, &amp;quot;score&amp;quot;: 5},\n                                &amp;quot;max_time_minute&amp;quot;: duration_minutes,\n                                &amp;quot;detour_tolerance_minute&amp;quot;: 0},\n                &amp;quot;start&amp;quot;: [50.942352665, 6.957777972392]\n                }\n            )\n        result = response.json()\n        landmarks = load_trip_landmarks(client, result[&amp;#x27;first_landmark_uuid&amp;#x27;])\n    \n        # Get computation time\n        comp_time = time.time() - start_time\n    \n        # Add details to report\n        log_trip_details(request, landmarks, result[&amp;#x27;total_time&amp;#x27;], duration_minutes)\n    \n        # for elem in landmarks :\n        #     print(elem)\n    \n        # checks :\n        assert response.status_code == 200  # check for successful planning\n&amp;gt;       assert comp_time &amp;lt; 30, f&amp;quot;Computation time exceeded 30 seconds: {comp_time:.2f} seconds&amp;quot;\nE       AssertionError: Computation time exceeded 30 seconds: 53.27 seconds\nE       assert 53.27033972740173 &amp;lt; 30\n\nsrc/tests/test_main.py:137: AssertionError\n\n------------------------------ Captured log call -------------------------------\nINFO     src.main:main.py:65 No end coordinates provided. Using start=end.\nINFO     src.main:main.py:97 Fetched 244 landmarks in  \t: 0.069 seconds\nINFO     src.main:main.py:122 Total computation time\t: 53.196 seconds\nINFO     src.main:main.py:127 Generated a trip of 253 minutes with 16 landmarks in 53.265 seconds.\nINFO     httpx:_client.py:1025 HTTP Request: POST http://testserver/trip/new &amp;quot;HTTP/1.1 200 OK&amp;quot;\n\n&#34;}], &#34;src/tests/test_main.py::test_strasbourg&#34;: [{&#34;extras&#34;: [], &#34;result&#34;: &#34;Passed&#34;, &#34;testId&#34;: &#34;src/tests/test_main.py::test_strasbourg&#34;, &#34;resultsTableRow&#34;: [&#34;&lt;td class=\&#34;col-result\&#34;&gt;Passed&lt;/td&gt;&#34;, &#34;&lt;td class=\&#34;col-testId\&#34;&gt;src/tests/test_main.py::test_strasbourg&lt;/td&gt;&#34;, &#34;&lt;td&gt;start (0 | 5) - 8 - \u00c9glise protestante Saint-Pierre-le-Jeune (347 | 5) - 6 - \u00c9glise catholique Saint-Pierre-le-Jeune (197 | 5) - 8 - H\u00f4tel de Ville (295 | 5) - 4 - De la Grande \u00eele \u00e0 la Neustadt (414 | 5) - 8 - Bains municipaux de Strasbourg (518 | 5) - 5 - \u00c9glise Saint-\u00c9tienne (259 | 5) - 20 - Centre Administratif Ville et Eurom\u00e9tropole de Strasbourg (405 | 5) - 8 - Porte de l&#39;H\u00f4pital (207 | 5) - 3 - \u00c9glise Saint-Nicolas (303 | 5) - 8 - Cath\u00e9drale Notre-Dame (728 | 10) - 8 - Circuit \u00ab Petite France \u00bb (414 | 5) - 9 - Barrage Vauban (391 | 5) - 10 - \u00c9glise Catholique Saint-Jean-Baptiste (281 | 5) - 1 - finish (0 | 5) - 0&lt;/td&gt;&#34;, &#34;&lt;td&gt;181 min&lt;/td&gt;&#34;, &#34;&lt;td&gt;180 min&lt;/td&gt;&#34;, &#34;&lt;td class=\&#34;col-duration\&#34;&gt;00:00:05&lt;/td&gt;&#34;, &#34;&lt;td class=\&#34;col-links\&#34;&gt;&lt;/td&gt;&#34;], &#34;log&#34;: &#34;------------------------------ Captured log call -------------------------------\nINFO     src.main:main.py:65 No end coordinates provided. Using start=end.\nINFO     src.main:main.py:97 Fetched 118 landmarks in  \t: 0.027 seconds\nINFO     src.main:main.py:122 Total computation time\t: 5.281 seconds\nINFO     src.main:main.py:127 Generated a trip of 181 minutes with 15 landmarks in 5.308 seconds.\nINFO     httpx:_client.py:1025 HTTP Request: POST http://testserver/trip/new &amp;quot;HTTP/1.1 200 OK&amp;quot;\n\n&#34;}], &#34;src/tests/test_main.py::test_zurich&#34;: [{&#34;extras&#34;: [], &#34;result&#34;: &#34;Passed&#34;, &#34;testId&#34;: &#34;src/tests/test_main.py::test_zurich&#34;, &#34;resultsTableRow&#34;: [&#34;&lt;td class=\&#34;col-result\&#34;&gt;Passed&lt;/td&gt;&#34;, &#34;&lt;td class=\&#34;col-testId\&#34;&gt;src/tests/test_main.py::test_zurich&lt;/td&gt;&#34;, &#34;&lt;td&gt;start (0 | 5) - 14 - Johanneskirche (351 | 5) - 11 - Evangelisch-Lutherische Kirche Z\u00fcrich (391 | 5) - 9 - Russisch-Orthodoxe Auferstehungskirche (369 | 5) - 6 - Liebfrauenkirche (281 | 5) - 11 - Predigerkirche (351 | 5) - 8 - St. Peter (489 | 5) - 5 - Grossm\u00fcnster (483 | 5) - 1 - Wasserkirche (238 | 5) - 3 - Fraum\u00fcnster (531 | 5) - 0 - Fraum\u00fcnster Kreuzgang (174 | 5) - 1 - Stadthaus (191 | 5) - 5 - Rebekkabrunnen (174 | 5) - 4 - Zentralhofbrunnen (173 | 5) - 5 - Augustinerkirche (238 | 5) - 4 - St. Anna-Kapelle (191 | 5) - 6 - Globus (369 | 30) - 5 - finish (0 | 5) - 0&lt;/td&gt;&#34;, &#34;&lt;td&gt;208 min&lt;/td&gt;&#34;, &#34;&lt;td&gt;180 min&lt;/td&gt;&#34;, &#34;&lt;td class=\&#34;col-duration\&#34;&gt;00:00:04&lt;/td&gt;&#34;, &#34;&lt;td class=\&#34;col-links\&#34;&gt;&lt;/td&gt;&#34;], &#34;log&#34;: &#34;------------------------------ Captured log call -------------------------------\nINFO     src.main:main.py:65 No end coordinates provided. Using start=end.\nINFO     src.main:main.py:97 Fetched 133 landmarks in  \t: 0.024 seconds\nINFO     src.main:main.py:122 Total computation time\t: 4.107 seconds\nINFO     src.main:main.py:127 Generated a trip of 208 minutes with 18 landmarks in 4.131 seconds.\nINFO     httpx:_client.py:1025 HTTP Request: POST http://testserver/trip/new &amp;quot;HTTP/1.1 200 OK&amp;quot;\n\n&#34;}], &#34;src/tests/test_main.py::test_paris&#34;: [{&#34;extras&#34;: [], &#34;result&#34;: &#34;Passed&#34;, &#34;testId&#34;: &#34;src/tests/test_main.py::test_paris&#34;, &#34;resultsTableRow&#34;: [&#34;&lt;td class=\&#34;col-result\&#34;&gt;Passed&lt;/td&gt;&#34;, &#34;&lt;td class=\&#34;col-testId\&#34;&gt;src/tests/test_main.py::test_paris&lt;/td&gt;&#34;, &#34;&lt;td&gt;start (0 | 5) - 21 - \u00c9glise Saint-Eug\u00e8ne Sainte-C\u00e9cile (871 | 5) - 21 - \u00c9glise Saint-Leu - Saint-Gilles (546 | 5) - 6 - Centre Georges Pompidou (1118 | 5) - 3 - \u00c9glise Saint-Merri (529 | 5) - 13 - Square Jean XXIII (492 | 5) - 12 - \u00c9glise Saint-\u00c9tienne-du-Mont (696 | 5) - 13 - Cath\u00e9drale Notre-Dame de Paris (1469 | 10) - 10 - Tour Saint-Jacques (793 | 5) - 7 - Sainte-Chapelle (1469 | 60) - 1 - Palais de Justice de Paris (531 | 5) - 9 - \u00c9glise Saint-Germain l&#39;Auxerrois (662 | 5) - 8 - Pyramide du Louvre (557 | 5) - 3 - Tunnel des Tuileries (506 | 5) - 3 - Palais du Louvre (891 | 5) - 6 - Temple de l&#39;Oratoire du Louvre (840 | 5) - 6 - Jardin Nelson Mandela (492 | 5) - 3 - finish (0 | 5) - 0&lt;/td&gt;&#34;, &#34;&lt;td&gt;290 min&lt;/td&gt;&#34;, &#34;&lt;td&gt;300 min&lt;/td&gt;&#34;, &#34;&lt;td class=\&#34;col-duration\&#34;&gt;00:00:07&lt;/td&gt;&#34;, &#34;&lt;td class=\&#34;col-links\&#34;&gt;&lt;/td&gt;&#34;], &#34;log&#34;: &#34;------------------------------ Captured log call -------------------------------\nINFO     src.main:main.py:65 No end coordinates provided. Using start=end.\nINFO     src.main:main.py:97 Fetched 363 landmarks in  \t: 0.077 seconds\nINFO     src.main:main.py:122 Total computation time\t: 7.226 seconds\nINFO     src.main:main.py:127 Generated a trip of 290 minutes with 18 landmarks in 7.304 seconds.\nINFO     httpx:_client.py:1025 HTTP Request: POST http://testserver/trip/new &amp;quot;HTTP/1.1 200 OK&amp;quot;\n\n&#34;}], &#34;src/tests/test_main.py::test_new_york&#34;: [{&#34;extras&#34;: [], &#34;result&#34;: &#34;Failed&#34;, &#34;testId&#34;: &#34;src/tests/test_main.py::test_new_york&#34;, &#34;resultsTableRow&#34;: [&#34;&lt;td class=\&#34;col-result\&#34;&gt;Failed&lt;/td&gt;&#34;, &#34;&lt;td class=\&#34;col-testId\&#34;&gt;src/tests/test_main.py::test_new_york&lt;/td&gt;&#34;, &#34;&lt;td&gt;start (0 | 5) - 7 - New Museum (406 | 60) - 8 - Capitale (810 | 5) - 10 - Columbus Park (646 | 5) - 3 - Thomas Paine Park (394 | 5) - 3 - Collect Pond Park (485 | 5) - 10 - Tribeca Park (455 | 5) - 4 - Albert Capsouto Park (454 | 5) - 7 - New York City Fire Museum (461 | 60) - 6 - Duarte Square (685 | 5) - 12 - Petrosino Square (394 | 5) - 5 - Saint Patrick&#39;s Old Cathedral (489 | 10) - 14 - Judson Memorial Church (518 | 5) - 12 - Grace Church (518 | 5) - 7 - Union Square Park (646 | 5) - 10 - Flatiron Building (780 | 5) - 5 - Cathedral of St. Sava (518 | 10) - 4 - Madison Square Park (646 | 5) - 7 - Calvary Church (461 | 5) - 17 - Immaculate Conception Church (546 | 5) - 6 - St. Nicholas of Myra Orthodox Church (546 | 5) - 8 - Saint Mark&#39;s in-the-Bowery (633 | 5) - 11 - finish (0 | 5) - 0&lt;/td&gt;&#34;, &#34;&lt;td&gt;406 min&lt;/td&gt;&#34;, &#34;&lt;td&gt;600 min&lt;/td&gt;&#34;, &#34;&lt;td class=\&#34;col-duration\&#34;&gt;735 ms&lt;/td&gt;&#34;, &#34;&lt;td class=\&#34;col-links\&#34;&gt;&lt;/td&gt;&#34;], &#34;log&#34;: &#34;client = &amp;lt;starlette.testclient.TestClient object at 0x7b7aaac3a000&amp;gt;\nrequest = &amp;lt;FixtureRequest for &amp;lt;Function test_new_york&amp;gt;&amp;gt;\n\n    def test_new_york(client, request) :   # pylint: disable=redefined-outer-name\n        &amp;quot;&amp;quot;&amp;quot;\n        Test n\u00b02 : Custom test in New York (les Halles) centre to ensure proper decision making in crowded area.\n    \n        Args:\n            client:\n            request:\n        &amp;quot;&amp;quot;&amp;quot;\n        start_time = time.time()  # Start timer\n        duration_minutes = 600\n    \n        response = client.post(\n            &amp;quot;/trip/new&amp;quot;,\n            json={\n                &amp;quot;preferences&amp;quot;: {&amp;quot;sightseeing&amp;quot;: {&amp;quot;type&amp;quot;: &amp;quot;sightseeing&amp;quot;, &amp;quot;score&amp;quot;: 5},\n                                &amp;quot;nature&amp;quot;: {&amp;quot;type&amp;quot;: &amp;quot;nature&amp;quot;, &amp;quot;score&amp;quot;: 5},\n                                &amp;quot;shopping&amp;quot;: {&amp;quot;type&amp;quot;: &amp;quot;shopping&amp;quot;, &amp;quot;score&amp;quot;: 5},\n                                &amp;quot;max_time_minute&amp;quot;: duration_minutes,\n                                &amp;quot;detour_tolerance_minute&amp;quot;: 0},\n                &amp;quot;start&amp;quot;: [40.72592726802, -73.9920434795]\n                }\n            )\n        result = response.json()\n        landmarks = load_trip_landmarks(client, result[&amp;#x27;first_landmark_uuid&amp;#x27;])\n    \n        # Get computation time\n        comp_time = time.time() - start_time\n    \n        # Add details to report\n        log_trip_details(request, landmarks, result[&amp;#x27;total_time&amp;#x27;], duration_minutes)\n    \n        # for elem in landmarks :\n        #     print(elem)\n    \n        # checks :\n        assert response.status_code == 200  # check for successful planning\n        assert comp_time &amp;lt; 30, f&amp;quot;Computation time exceeded 30 seconds: {comp_time:.2f} seconds&amp;quot;\n&amp;gt;       assert duration_minutes*0.8 &amp;lt; result[&amp;#x27;total_time&amp;#x27;], f&amp;quot;Trip too short: {result[&amp;#x27;total_time&amp;#x27;]} instead of {duration_minutes}&amp;quot;\nE       AssertionError: Trip too short: 406 instead of 600\nE       assert (600 * 0.8) &amp;lt; 406\n\nsrc/tests/test_main.py:302: AssertionError\n\n------------------------------ Captured log call -------------------------------\nINFO     src.main:main.py:65 No end coordinates provided. Using start=end.\nINFO     src.main:main.py:97 Fetched 211 landmarks in  \t: 0.028 seconds\nINFO     src.main:main.py:122 Total computation time\t: 0.701 seconds\nINFO     src.main:main.py:127 Generated a trip of 406 minutes with 23 landmarks in 0.729 seconds.\nINFO     httpx:_client.py:1025 HTTP Request: POST http://testserver/trip/new &amp;quot;HTTP/1.1 200 OK&amp;quot;\n\n&#34;}], &#34;src/tests/test_main.py::test_shopping&#34;: [{&#34;extras&#34;: [], &#34;result&#34;: &#34;Failed&#34;, &#34;testId&#34;: &#34;src/tests/test_main.py::test_shopping&#34;, &#34;resultsTableRow&#34;: [&#34;&lt;td class=\&#34;col-result\&#34;&gt;Failed&lt;/td&gt;&#34;, &#34;&lt;td class=\&#34;col-testId\&#34;&gt;src/tests/test_main.py::test_shopping&lt;/td&gt;&#34;, &#34;&lt;td&gt;start (0 | 5) - 9 - Shopping Area (538 | 40) - 4 - Grand Bazar (93 | 30) - 20 - Halles de Lyon Paul Bocuse (272 | 30) - 7 - Galeries Lafayette (197 | 30) - 3 - Westfield La Part-Dieu (546 | 30) - 2 - Muji (259 | 30) - 25 - Grand H\u00f4tel-Dieu (546 | 30) - 5 - finish (0 | 5) - 0&lt;/td&gt;&#34;, &#34;&lt;td&gt;300 min&lt;/td&gt;&#34;, &#34;&lt;td&gt;240 min&lt;/td&gt;&#34;, &#34;&lt;td class=\&#34;col-duration\&#34;&gt;60 ms&lt;/td&gt;&#34;, &#34;&lt;td class=\&#34;col-links\&#34;&gt;&lt;/td&gt;&#34;], &#34;log&#34;: &#34;client = &amp;lt;starlette.testclient.TestClient object at 0x7b7aaac3a000&amp;gt;\nrequest = &amp;lt;FixtureRequest for &amp;lt;Function test_shopping&amp;gt;&amp;gt;\n\n    def test_shopping(client, request) :   # pylint: disable=redefined-outer-name\n        &amp;quot;&amp;quot;&amp;quot;\n        Test n\u00b03 : Custom test in Lyon centre to ensure shopping clusters are found.\n    \n        Args:\n            client:\n            request:\n        &amp;quot;&amp;quot;&amp;quot;\n        start_time = time.time()  # Start timer\n        duration_minutes = 240\n    \n        response = client.post(\n            &amp;quot;/trip/new&amp;quot;,\n            json={\n                &amp;quot;preferences&amp;quot;: {&amp;quot;sightseeing&amp;quot;: {&amp;quot;type&amp;quot;: &amp;quot;sightseeing&amp;quot;, &amp;quot;score&amp;quot;: 0},\n                                &amp;quot;nature&amp;quot;: {&amp;quot;type&amp;quot;: &amp;quot;nature&amp;quot;, &amp;quot;score&amp;quot;: 0},\n                                &amp;quot;shopping&amp;quot;: {&amp;quot;type&amp;quot;: &amp;quot;shopping&amp;quot;, &amp;quot;score&amp;quot;: 5},\n                                &amp;quot;max_time_minute&amp;quot;: duration_minutes,\n                                &amp;quot;detour_tolerance_minute&amp;quot;: 0},\n                &amp;quot;start&amp;quot;: [45.7576485, 4.8330241]\n                }\n            )\n        result = response.json()\n        landmarks = load_trip_landmarks(client, result[&amp;#x27;first_landmark_uuid&amp;#x27;])\n    \n        # Get computation time\n        comp_time = time.time() - start_time\n    \n        # Add details to report\n        log_trip_details(request, landmarks, result[&amp;#x27;total_time&amp;#x27;], duration_minutes)\n    \n        for elem in landmarks :\n            print(elem)\n    \n        # checks :\n        assert response.status_code == 200  # check for successful planning\n        assert comp_time &amp;lt; 30, f&amp;quot;Computation time exceeded 30 seconds: {comp_time:.2f} seconds&amp;quot;\n        assert duration_minutes*0.8 &amp;lt; result[&amp;#x27;total_time&amp;#x27;], f&amp;quot;Trip too short: {result[&amp;#x27;total_time&amp;#x27;]} instead of {duration_minutes}&amp;quot;\n&amp;gt;       assert duration_minutes*1.2 &amp;gt; result[&amp;#x27;total_time&amp;#x27;], f&amp;quot;Trip too long: {result[&amp;#x27;total_time&amp;#x27;]} instead of {duration_minutes}&amp;quot;\nE       AssertionError: Trip too long: 300 instead of 240\nE       assert (240 * 1.2) &amp;gt; 300\n\nsrc/tests/test_main.py:344: AssertionError\n\n----------------------------- Captured stdout call -----------------------------\nLandmark(start): [start @(45.7576485, 4.8330241), score=0, time_to_next=9]\nLandmark(shopping): [Shopping Area @(np.float64(45.76223053940519), np.float64(4.833794685873603)), score=538, time_to_next=4]\nLandmark(shopping): [Grand Bazar @(45.7632141, 4.8361975), score=93, time_to_next=20]\nLandmark(shopping): [Halles de Lyon Paul Bocuse @(45.7628282, 4.8505601), score=272, time_to_next=7]\nLandmark(shopping): [Galeries Lafayette @(45.7627107, 4.8556833), score=197, time_to_next=3]\nLandmark(shopping): [Westfield La Part-Dieu @(45.761331, 4.855676), score=546, time_to_next=2]\nLandmark(shopping): [Muji @(45.7615971, 4.8543781), score=259, time_to_next=25]\nLandmark(shopping): [Grand H\u00f4tel-Dieu @(45.7586955, 4.8364597), score=546, time_to_next=5]\nLandmark(finish): [finish @(45.7576485, 4.8330241), score=0]\n\n------------------------------ Captured log call -------------------------------\nINFO     src.main:main.py:65 No end coordinates provided. Using start=end.\nINFO     src.main:main.py:97 Fetched 7 landmarks in  \t: 0.009 seconds\nINFO     src.main:main.py:122 Total computation time\t: 0.047 seconds\nINFO     src.main:main.py:127 Generated a trip of 300 minutes with 9 landmarks in 0.056 seconds.\nINFO     httpx:_client.py:1025 HTTP Request: POST http://testserver/trip/new &amp;quot;HTTP/1.1 200 OK&amp;quot;\n\n&#34;}]}, &#34;renderCollapsed&#34;: [&#34;passed&#34;], &#34;initialSort&#34;: &#34;result&#34;, &#34;title&#34;: &#34;Backend Testing Report&#34;}"></div>
+    <div id="data-container" data-jsonblob="{&#34;environment&#34;: {&#34;Python&#34;: &#34;3.12.3&#34;, &#34;Platform&#34;: &#34;Linux-6.8.0-51-generic-x86_64-with-glibc2.39&#34;, &#34;Packages&#34;: {&#34;pytest&#34;: &#34;8.3.4&#34;, &#34;pluggy&#34;: &#34;1.5.0&#34;}, &#34;Plugins&#34;: {&#34;html&#34;: &#34;4.1.1&#34;, &#34;anyio&#34;: &#34;4.8.0&#34;, &#34;metadata&#34;: &#34;3.1.1&#34;}}, &#34;tests&#34;: {&#34;src/tests/test_main.py::test_turckheim&#34;: [{&#34;extras&#34;: [], &#34;result&#34;: &#34;Passed&#34;, &#34;testId&#34;: &#34;src/tests/test_main.py::test_turckheim&#34;, &#34;resultsTableRow&#34;: [&#34;&lt;td class=\&#34;col-result\&#34;&gt;Passed&lt;/td&gt;&#34;, &#34;&lt;td class=\&#34;col-testId\&#34;&gt;src/tests/test_main.py::test_turckheim&lt;/td&gt;&#34;, &#34;&lt;td&gt;start (0 | 0) - 6 - H\u00f4tel de ville (238 | 5) - 1 - H\u00f4tel des Deux-Clefs (217 | 5) - 6 - finish (0 | 0) - 0&lt;/td&gt;&#34;, &#34;&lt;td&gt;23 min&lt;/td&gt;&#34;, &#34;&lt;td&gt;20 min&lt;/td&gt;&#34;, &#34;&lt;td class=\&#34;col-duration\&#34;&gt;161 ms&lt;/td&gt;&#34;, &#34;&lt;td class=\&#34;col-links\&#34;&gt;&lt;/td&gt;&#34;], &#34;log&#34;: &#34;------------------------------ Captured log call -------------------------------\nDEBUG    asyncio:selector_events.py:64 Using selector: EpollSelector\nINFO     src.main:main.py:66 No end coordinates provided. Using start=end.\nDEBUG    src.utils.landmarks_manager:landmarks_manager.py:79 Starting to fetch landmarks...\nDEBUG    src.utils.landmarks_manager:landmarks_manager.py:91 Fetching sightseeing landmarks...\nDEBUG    src.overpass.overpass:overpass.py:118 Cache hit.\nDEBUG    src.overpass.overpass:overpass.py:118 Cache hit.\nDEBUG    src.overpass.overpass:overpass.py:118 Cache hit.\nDEBUG    src.overpass.overpass:overpass.py:118 Cache hit.\nDEBUG    src.overpass.overpass:overpass.py:118 Cache hit.\nDEBUG    src.overpass.overpass:overpass.py:118 Cache hit.\nDEBUG    src.utils.landmarks_manager:landmarks_manager.py:209 Fetched 20 landmarks of type sightseeing in (48.079458619727674, 7.272726663391359, 48.08971738027232, 7.288083336608641)\nDEBUG    src.utils.landmarks_manager:landmarks_manager.py:94 Fetching sightseeing clusters...\nDEBUG    src.overpass.overpass:overpass.py:118 Cache hit.\nDEBUG    src.utils.cluster_manager:cluster_manager.py:146 Detected 0 sightseeing clusters.\nDEBUG    src.utils.landmarks_manager:landmarks_manager.py:100 Sightseeing clusters done\nINFO     src.main:main.py:100 Fetched 17 landmarks in  \t: 0.006 seconds\nDEBUG    src.optimization.optimizer:optimizer.py:580 First results are out. Looking out for circles and correcting.\nDEBUG    src.optimization.optimizer:optimizer.py:617 Re-optimized 0 times, objective value : 455\nDEBUG    src.optimization.refiner:refiner.py:345 Using 4 minor landmarks around the predicted path\nDEBUG    src.optimization.optimizer:optimizer.py:580 First results are out. Looking out for circles and correcting.\nDEBUG    src.optimization.optimizer:optimizer.py:617 Re-optimized 0 times, objective value : 455\nDEBUG    src.main:main.py:123 First stage optimization\t: 0.059 seconds\nDEBUG    src.main:main.py:124 Second stage optimization\t: 0.022 seconds\nINFO     src.main:main.py:125 Total computation time\t: 0.082 seconds\nINFO     src.main:main.py:130 Generated a trip of 23 minutes with 4 landmarks in 0.087 seconds.\nINFO     httpx:_client.py:1025 HTTP Request: POST http://testserver/trip/new &amp;quot;HTTP/1.1 200 OK&amp;quot;\n\n&#34;}], &#34;src/tests/test_main.py::test_bellecour&#34;: [{&#34;extras&#34;: [], &#34;result&#34;: &#34;Passed&#34;, &#34;testId&#34;: &#34;src/tests/test_main.py::test_bellecour&#34;, &#34;resultsTableRow&#34;: [&#34;&lt;td class=\&#34;col-result\&#34;&gt;Passed&lt;/td&gt;&#34;, &#34;&lt;td class=\&#34;col-testId\&#34;&gt;src/tests/test_main.py::test_bellecour&lt;/td&gt;&#34;, &#34;&lt;td&gt;start (0 | 0) - 5 - H\u00f4tel de l&#39;Europe (217 | 5) - 4 - Palais archi\u00e9piscopal (217 | 5) - 1 - Cath\u00e9drale Saint-Jean (347 | 10) - 5 - Impasse Turquet (259 | 5) - 2 - \u00c9glise Saint-Georges (461 | 5) - 9 - Chapelle Saint-Thomas (259 | 5) - 0 - Basilique de Fourvi\u00e8re (324 | 5) - 5 - Site historique de Lyon (414 | 5) - 4 - Temple du Change (406 | 5) - 4 - \u00c9glise Saint-Paul (238 | 5) - 4 - \u00c9glise Notre-Dame-Saint-Vincent (325 | 5) - 8 - \u00c9glise Saint-Nizier (351 | 5) - 14 - finish (0 | 0) - 0&lt;/td&gt;&#34;, &#34;&lt;td&gt;130 min&lt;/td&gt;&#34;, &#34;&lt;td&gt;120 min&lt;/td&gt;&#34;, &#34;&lt;td class=\&#34;col-duration\&#34;&gt;00:00:02&lt;/td&gt;&#34;, &#34;&lt;td class=\&#34;col-links\&#34;&gt;&lt;/td&gt;&#34;], &#34;log&#34;: &#34;------------------------------ Captured log call -------------------------------\nDEBUG    asyncio:selector_events.py:64 Using selector: EpollSelector\nINFO     src.main:main.py:66 No end coordinates provided. Using start=end.\nDEBUG    src.utils.landmarks_manager:landmarks_manager.py:79 Starting to fetch landmarks...\nDEBUG    src.utils.landmarks_manager:landmarks_manager.py:91 Fetching sightseeing landmarks...\nDEBUG    src.overpass.overpass:overpass.py:118 Cache hit.\nDEBUG    src.overpass.overpass:overpass.py:118 Cache hit.\nDEBUG    src.overpass.overpass:overpass.py:118 Cache hit.\nDEBUG    src.overpass.overpass:overpass.py:118 Cache hit.\nDEBUG    src.overpass.overpass:overpass.py:118 Cache hit.\nDEBUG    src.overpass.overpass:overpass.py:118 Cache hit.\nDEBUG    src.utils.landmarks_manager:landmarks_manager.py:209 Fetched 351 landmarks of type sightseeing in (45.73968219431761, 4.807273148692414, 45.775614805682395, 4.858775051307586)\nDEBUG    src.utils.landmarks_manager:landmarks_manager.py:94 Fetching sightseeing clusters...\nDEBUG    src.overpass.overpass:overpass.py:118 Cache hit.\nDEBUG    src.utils.cluster_manager:cluster_manager.py:138 Found 3 different clusters.\nDEBUG    src.overpass.overpass:overpass.py:118 Cache hit.\nDEBUG    src.overpass.overpass:overpass.py:118 Cache hit.\nDEBUG    src.utils.landmarks_manager:landmarks_manager.py:100 Sightseeing clusters done\nDEBUG    src.utils.landmarks_manager:landmarks_manager.py:104 Fetching nature landmarks...\nDEBUG    src.overpass.overpass:overpass.py:118 Cache hit.\nDEBUG    src.overpass.overpass:overpass.py:118 Cache hit.\nDEBUG    src.overpass.overpass:overpass.py:118 Cache hit.\nDEBUG    src.overpass.overpass:overpass.py:118 Cache hit.\nDEBUG    src.overpass.overpass:overpass.py:118 Cache hit.\nDEBUG    src.overpass.overpass:overpass.py:118 Cache hit.\nDEBUG    src.utils.landmarks_manager:landmarks_manager.py:209 Fetched 352 landmarks of type nature in (45.73968219431761, 4.807273148692414, 45.775614805682395, 4.858775051307586)\nDEBUG    src.utils.landmarks_manager:landmarks_manager.py:111 Fetching shopping landmarks...\nDEBUG    src.overpass.overpass:overpass.py:118 Cache hit.\nDEBUG    src.utils.landmarks_manager:landmarks_manager.py:209 Fetched 13 landmarks of type shopping in (45.73968219431761, 4.807273148692414, 45.775614805682395, 4.858775051307586)\nDEBUG    src.utils.landmarks_manager:landmarks_manager.py:113 Fetching shopping clusters...\nDEBUG    src.overpass.overpass:overpass.py:118 Cache hit.\nDEBUG    src.utils.cluster_manager:cluster_manager.py:138 Found 7 different clusters.\nDEBUG    src.overpass.overpass:overpass.py:118 Cache hit.\nDEBUG    src.overpass.overpass:overpass.py:118 Cache hit.\nDEBUG    src.overpass.overpass:overpass.py:118 Cache hit.\nDEBUG    src.overpass.overpass:overpass.py:118 Cache hit.\nDEBUG    src.overpass.overpass:overpass.py:118 Cache hit.\nDEBUG    src.overpass.overpass:overpass.py:118 Cache hit.\nDEBUG    src.overpass.overpass:overpass.py:118 Cache hit.\nDEBUG    src.overpass.overpass:overpass.py:118 Cache hit.\nDEBUG    src.overpass.overpass:overpass.py:118 Cache hit.\nDEBUG    src.overpass.overpass:overpass.py:118 Cache hit.\nDEBUG    src.utils.landmarks_manager:landmarks_manager.py:124 Shopping clusters done\nINFO     src.main:main.py:100 Fetched 626 landmarks in  \t: 0.112 seconds\nDEBUG    src.optimization.optimizer:optimizer.py:580 First results are out. Looking out for circles and correcting.\nDEBUG    src.optimization.optimizer:optimizer.py:617 Re-optimized 4 times, objective value : 3389\nDEBUG    src.optimization.refiner:refiner.py:345 Using 15 minor landmarks around the predicted path\nDEBUG    src.optimization.optimizer:optimizer.py:580 First results are out. Looking out for circles and correcting.\nDEBUG    src.optimization.optimizer:optimizer.py:617 Re-optimized 2 times, objective value : 3818\nDEBUG    src.main:main.py:123 First stage optimization\t: 1.675 seconds\nDEBUG    src.main:main.py:124 Second stage optimization\t: 0.706 seconds\nINFO     src.main:main.py:125 Total computation time\t: 2.382 seconds\nINFO     src.main:main.py:130 Generated a trip of 130 minutes with 14 landmarks in 2.493 seconds.\nINFO     httpx:_client.py:1025 HTTP Request: POST http://testserver/trip/new &amp;quot;HTTP/1.1 200 OK&amp;quot;\n\n&#34;}]}, &#34;renderCollapsed&#34;: [&#34;passed&#34;], &#34;initialSort&#34;: &#34;result&#34;, &#34;title&#34;: &#34;Backend Testing Report&#34;}"></div>
     <script>
       (function(){function r(e,n,t){function o(i,f){if(!n[i]){if(!e[i]){var c="function"==typeof require&&require;if(!f&&c)return c(i,!0);if(u)return u(i,!0);var a=new Error("Cannot find module '"+i+"'");throw a.code="MODULE_NOT_FOUND",a}var p=n[i]={exports:{}};e[i][0].call(p.exports,function(r){var n=e[i][1][r];return o(n||r)},p,p.exports,r,e,n,t)}return n[i].exports}for(var u="function"==typeof require&&require,i=0;i<t.length;i++)o(t[i]);return o}return r})()({1:[function(require,module,exports){
 const { getCollapsedCategory, setCollapsedIds } = require('./storage.js')
diff --git a/backend/src/constants.py b/backend/src/constants.py
index 60a26c7..61e215c 100644
--- a/backend/src/constants.py
+++ b/backend/src/constants.py
@@ -2,6 +2,7 @@
 
 import os
 from pathlib import Path
+from typing import List, Literal
 
 
 LOCATION_PREFIX = Path('src')
@@ -14,6 +15,7 @@ OPTIMIZER_PARAMETERS_PATH = PARAMETERS_DIR / 'optimizer_parameters.yaml'
 cache_dir_string = os.getenv('OSM_CACHE_DIR', './cache')
 OSM_CACHE_DIR = Path(cache_dir_string)
 
+OSM_TYPES = List[Literal['way', 'node', 'relation']]
 
 MEMCACHED_HOST_PATH = os.getenv('MEMCACHED_HOST_PATH', None)
 if MEMCACHED_HOST_PATH == "none":
diff --git a/backend/src/main.py b/backend/src/main.py
index cdae598..b5d9d35 100644
--- a/backend/src/main.py
+++ b/backend/src/main.py
@@ -3,7 +3,7 @@
 import logging
 import time
 from contextlib import asynccontextmanager
-from fastapi import FastAPI, HTTPException, Query
+from fastapi import FastAPI, HTTPException, BackgroundTasks, Query
 
 from .logging_config import configure_logging
 from .structs.landmark import Landmark, Toilets
@@ -14,8 +14,10 @@ from .utils.landmarks_manager import LandmarkManager
 from .utils.toilets_manager import ToiletsManager
 from .optimization.optimizer import Optimizer
 from .optimization.refiner import Refiner
+from .overpass.overpass import fill_cache
 from .cache import client as cache_client
 
+
 logger = logging.getLogger(__name__)
 
 manager = LandmarkManager()
@@ -35,7 +37,6 @@ async def lifespan(app: FastAPI):
 app = FastAPI(lifespan=lifespan)
 
 
-
 @app.post("/trip/new")
 def new_trip(preferences: Preferences,
              start: tuple[float, float],
@@ -127,6 +128,9 @@ def new_trip(preferences: Preferences,
     # upon creation of the trip, persistence of both the trip and its landmarks is ensured.
     trip = Trip.from_linked_landmarks(linked_tour, cache_client)
     logger.info(f'Generated a trip of {trip.total_time} minutes with {len(refined_tour)} landmarks in {round(t_generate_landmarks + t_first_stage + t_second_stage,3)} seconds.')
+    
+    background_tasks = BackgroundTasks(fill_cache())
+
     return trip
 
 
diff --git a/backend/src/overpass/caching_strategy.py b/backend/src/overpass/caching_strategy.py
index 9ca11b7..750ad62 100644
--- a/backend/src/overpass/caching_strategy.py
+++ b/backend/src/overpass/caching_strategy.py
@@ -1,9 +1,9 @@
-"""Module defining the caching strategy for overpass requests."""
 import os
 import xml.etree.ElementTree as ET
 import hashlib
+import time
 
-from ..constants import OSM_CACHE_DIR
+from ..constants import OSM_CACHE_DIR, OSM_TYPES
 
 
 def get_cache_key(query: str) -> str:
@@ -13,14 +13,9 @@ def get_cache_key(query: str) -> str:
     """
     return hashlib.md5(query.encode('utf-8')).hexdigest()
 
-
 class CachingStrategyBase:
     """
     Base class for implementing caching strategies.
-
-    This class defines the structure for a caching strategy with basic methods
-    that must be implemented by subclasses. Subclasses should define how to
-    retrieve, store, and close the cache.
     """
     def get(self, key):
         """Retrieve the cached data associated with the provided key."""
@@ -30,6 +25,15 @@ class CachingStrategyBase:
         """Store data in the cache with the specified key."""
         raise NotImplementedError('Subclass should implement set')
 
+    def set_hollow(self, key, cell: tuple, osm_types: OSM_TYPES,
+                    selector: str, conditions=[], out='center'):
+        """Create a hollow (empty) cache entry with a specific key."""
+        raise NotImplementedError('Subclass should implement set_hollow')
+
+    def fill_hollow(self, key, value):
+        """Fill in the cache for an existing hollow entry."""
+        raise NotImplementedError('Subclass should implement fill_hollow')
+
     def close(self):
         """Clean up or close any resources used by the caching strategy."""
 
@@ -37,22 +41,10 @@ class CachingStrategyBase:
 class XMLCache(CachingStrategyBase):
     """
     A caching strategy that stores and retrieves data in XML format.
-
-    This class provides methods to cache data as XML files in a specified directory.
-    The directory is automatically suffixed with '_XML' to distinguish it from other
-    caching strategies. The data is stored and retrieved using XML serialization.
-
-    Args:
-        cache_dir (str): The base directory where XML cache files will be stored.
-                         Defaults to 'OSM_CACHE_DIR' with a '_XML' suffix.
-
-    Methods:
-        get(key): Retrieve cached data from a XML file associated with the given key.
-        set(key, value): Store data in a XML file with the specified key.
     """
     def __init__(self, cache_dir=OSM_CACHE_DIR):
         # Add the class name as a suffix to the directory
-        self._cache_dir = f'{cache_dir}_XML'
+        self._cache_dir = f'{cache_dir}'
         if not os.path.exists(self._cache_dir):
             os.makedirs(self._cache_dir)
 
@@ -68,7 +60,6 @@ class XMLCache(CachingStrategyBase):
                 tree = ET.parse(filename)
                 return tree.getroot()  # Return the root element of the parsed XML
             except ET.ParseError:
-                # print(f"Error parsing cached XML file: {filename}")
                 return None
         return None
 
@@ -77,25 +68,41 @@ class XMLCache(CachingStrategyBase):
         filename = self._filename(key)
         tree = ET.ElementTree(value)  # value is expected to be an ElementTree root element
         try:
-            # Write the XML data to a file
             with open(filename, 'wb') as file:
                 tree.write(file, encoding='utf-8', xml_declaration=True)
         except IOError as e:
             raise IOError(f"Error writing to cache file: {filename} - {e}") from e
 
+    def set_hollow(self, key, cell: tuple, osm_types: OSM_TYPES,
+                    selector: str, conditions=[], out='center'):
+        """Create an empty placeholder cache entry for a future fill."""
+        hollow_key = f'hollow_{key}'
+        filename = self._filename(hollow_key)
+    
+        # Create the root element <cache>
+        root = ET.Element("params")
+        # Add sub-elements with provided values
+        ET.SubElement(root, "key").text = key
+        ET.SubElement(root, "cell").text = f"({cell[0]}, {cell[1]})"
+        ET.SubElement(root, "osm_types").text = ','.join(osm_types)
+        ET.SubElement(root, "selector").text = selector
+        ET.SubElement(root, "conditions").text = ','.join(conditions) if conditions else "none"
+        ET.SubElement(root, "out").text = out
+
+        # Create an ElementTree object from the root
+        tree = ET.ElementTree(root)
+
+        # Write the XML to the file
+        with open(filename, 'wb') as file:
+            tree.write(file, encoding='utf-8', xml_declaration=True)
+
+    def close(self):
+        """Cleanup method, if needed."""
+        pass
 
 class CachingStrategy:
     """
     A class to manage different caching strategies.
-
-    This class provides an interface to switch between different caching strategies 
-    (e.g., XMLCache, JSONCache) dynamically. It allows caching data in different formats, 
-    depending on the strategy being used. By default, it uses the XMLCache strategy.
-
-    Attributes:
-    __strategy (CachingStrategyBase): The currently active caching strategy.
-    __strategies (dict): A mapping between strategy names (as strings) and their corresponding
-                         classes, allowing dynamic selection of caching strategies.
     """
     __strategy = XMLCache()  # Default caching strategy
     __strategies = {
@@ -104,37 +111,31 @@ class CachingStrategy:
 
     @classmethod
     def use(cls, strategy_name='XML', **kwargs):
-        """
-        Set the caching strategy based on the strategy_name provided.
-
-        Args:
-            strategy_name (str): The name of the caching strategy (e.g., 'XML').
-            **kwargs: Additional keyword arguments to pass when initializing the strategy.
-        """
-        # If a previous strategy exists, close it
         if cls.__strategy:
             cls.__strategy.close()
 
-        # Retrieve the strategy class based on the strategy name
         strategy_class = cls.__strategies.get(strategy_name)
-
         if not strategy_class:
             raise ValueError(f"Unknown caching strategy: {strategy_name}")
 
-        # Instantiate the new strategy with the provided arguments
         cls.__strategy = strategy_class(**kwargs)
         return cls.__strategy
 
     @classmethod
     def get(cls, key):
-        """Get data from the current strategy's cache."""
-        if not cls.__strategy:
-            raise RuntimeError("Caching strategy has not been set.")
         return cls.__strategy.get(key)
 
     @classmethod
     def set(cls, key, value):
-        """Set data in the current strategy's cache."""
-        if not cls.__strategy:
-            raise RuntimeError("Caching strategy has not been set.")
         cls.__strategy.set(key, value)
+
+    @classmethod
+    def set_hollow(cls, key, cell: tuple, osm_types: OSM_TYPES,
+                    selector: str, conditions=[], out='center'):
+        """Create a hollow cache entry."""
+        cls.__strategy.set_hollow(key, cell, osm_types, selector, conditions, out)
+
+    @classmethod
+    def fill_hollow(cls, key, value):
+        """Fill in the hollow cache entry with actual data."""
+        cls.__strategy.fill_hollow(key, value)
diff --git a/backend/src/overpass/overpass.py b/backend/src/overpass/overpass.py
index 505053c..1318777 100644
--- a/backend/src/overpass/overpass.py
+++ b/backend/src/overpass/overpass.py
@@ -1,14 +1,15 @@
 """Module allowing connexion to overpass api and fectch data from OSM."""
-from typing import Literal, List
+import os
 import urllib
+import math
 import logging
 import xml.etree.ElementTree as ET
 
 from .caching_strategy import get_cache_key, CachingStrategy
-from ..constants import OSM_CACHE_DIR
+from ..constants import OSM_CACHE_DIR, OSM_TYPES
 
-logger = logging.getLogger('Overpass')
-osm_types = List[Literal['way', 'node', 'relation']]
+
+RESOLUTION = 0.05
 
 
 class Overpass :
@@ -16,6 +17,9 @@ class Overpass :
     Overpass class to manage the query building and sending to overpass api.
     The caching strategy is a part of this class and initialized upon creation of the Overpass object.
     """
+    logger = logging.getLogger(__name__)
+
+
     def __init__(self, caching_strategy: str = 'XML', cache_dir: str = OSM_CACHE_DIR) :
         """
         Initialize the Overpass instance with the url, headers and caching strategy.
@@ -26,16 +30,14 @@ class Overpass :
 
 
     @classmethod
-    def build_query(self, area: tuple, osm_types: osm_types,
+    def build_query(self, bbox: tuple, osm_types: OSM_TYPES,
                     selector: str, conditions=[], out='center') -> str:
         """
         Constructs a query string for the Overpass API to retrieve OpenStreetMap (OSM) data.
 
         Args:
-            area (tuple): A tuple representing the geographical search area, typically in the format 
-                        (radius, latitude, longitude). The first element is a string like "around:2000" 
-                        specifying the search radius, and the second and third elements represent 
-                        the latitude and longitude as floats or strings.
+            bbox (tuple): A tuple representing the geographical search area, typically in the format 
+                        (lat_min, lon_min, lat_max, lon_max).
             osm_types (list[str]): A list of OSM element types to search for. Must be one or more of 
                                     'Way', 'Node', or 'Relation'.
             selector (str): The key or tag to filter the OSM elements (e.g., 'amenity', 'highway', etc.).
@@ -52,7 +54,6 @@ class Overpass :
         Notes:
             - If no conditions are provided, the query will just use the `selector` to filter the OSM 
             elements without additional constraints.
-            - The search area must always formatted as "(radius, lat, lon)".
         """
         if not isinstance(conditions, list) :
             conditions = [conditions]
@@ -61,15 +62,8 @@ class Overpass :
 
         query = '('
 
-        # Round the radius to nearest 50 and coordinates to generate less queries
-        if area[0] > 500 :
-            search_radius = round(area[0] / 50) * 50
-            loc = tuple((round(area[1], 2), round(area[2], 2)))
-        else :
-            search_radius = round(area[0] / 25) * 25
-            loc = tuple((round(area[1], 3), round(area[2], 3)))
-
-        search_area = f"(around:{search_radius}, {str(loc[0])}, {str(loc[1])})"
+        # convert the bbox to string.
+        bbox_str = f"({','.join(map(str, bbox))})"
 
         if conditions :
             conditions = '(if: ' + ' && '.join(conditions) + ')'
@@ -77,14 +71,15 @@ class Overpass :
             conditions = ''
 
         for elem in osm_types :
-            query += elem + '[' + selector + ']' + conditions + search_area + ';'
+            query += elem + '[' + selector + ']' + conditions + bbox_str + ';'
 
         query += ');' + f'out {out};'
 
         return query
 
 
-    def send_query(self, query: str) -> ET:
+    def send_query(self, bbox: tuple, osm_types: OSM_TYPES,
+                    selector: str, conditions=[], out='center') -> ET:
         """
         Sends the Overpass QL query to the Overpass API and returns the parsed JSON response.
 
@@ -94,18 +89,42 @@ class Overpass :
         Returns:
             dict: The parsed JSON response from the Overpass API, or None if the request fails.
         """
+        # Determine which grid cells overlap with this bounding box.
+        overlapping_cells = self.get_overlapping_cells(bbox)
 
-        # Generate a cache key for the current query
-        cache_key = get_cache_key(query)
+        # Check the cache for any data that overlaps with these cells
+        cell_key_dict = {}
+        for cell in overlapping_cells :
+            for elem in osm_types :
+                key_str = f"{elem}[{selector}]{conditions}({','.join(map(str, cell))})"
+            
+            cell_key_dict[cell] = get_cache_key(key_str)
 
-        # Try to fetch the result from the cache
-        cached_response = self.caching_strategy.get(cache_key)
-        if cached_response is not None :
-            logger.debug("Cache hit.")
-            return cached_response
+        cached_responses = []
+        hollow_cache_keys = []
+
+        # Retrieve the cached data and mark the missing entries as hollow
+        for cell, key in cell_key_dict.items():
+            cached_data = self.caching_strategy.get(key)
+            if cached_data is not None :
+                cached_responses.append(cached_data)
+            else:
+                # Cache miss: Mark the cache key as hollow
+                self.caching_strategy.set_hollow(key, cell, osm_types, selector, conditions, out)
+                hollow_cache_keys.append(key)
+
+        # If there is no missing data, return the cached responses
+        if not hollow_cache_keys :
+            self.logger.debug(f'Cache hit.')
+            return self.combine_cached_data(cached_responses)
+        
+        # TODO If there is SOME missing data : hybrid stuff with partial cache
+        
+        # Build the query string in case of needed overpass query
+        query_str = self.build_query(bbox, osm_types, selector, conditions, out)
 
         # Prepare the data to be sent as POST request, encoded as bytes
-        data = urllib.parse.urlencode({'data': query}).encode('utf-8')
+        data = urllib.parse.urlencode({'data': query_str}).encode('utf-8')
 
         try:
             # Create a Request object with the specified URL, data, and headers
@@ -117,9 +136,7 @@ class Overpass :
                 response_data = response.read().decode('utf-8')
                 root = ET.fromstring(response_data)
 
-                # Cache the response data as an ElementTree root
-                self.caching_strategy.set(cache_key, root)
-                logger.debug("Response data added to cache.")
+                self.logger.debug(f'Cache miss. Fetching data through Overpass\nQuery = {query_str}')
 
                 return root
 
@@ -127,7 +144,108 @@ class Overpass :
             raise ConnectionError(f"Error connecting to Overpass API: {e}") from e
 
 
-def get_base_info(elem: ET.Element, osm_type: osm_types, with_name=False) :
+    def build_query_from_hollow(self, xml_string):
+        """Extract variables from an XML string."""
+        
+        # Parse the XML string into an ElementTree object
+        root = ET.fromstring(xml_string)
+        
+        # Extract values from the XML tree
+        key = root.find('key').text
+        cell = tuple(map(float, root.find('cell').text.strip('()').split(',')))
+        bbox = self.get_bbox_from_grid_cell(cell[0], cell[1])
+        osm_types = root.find('osm_types').text.split(',')
+        selector = root.find('selector').text
+        conditions = root.find('conditions').text.split(',') if root.find('conditions').text != "none" else []
+        out = root.find('out').text
+
+        query_str = self.build_query(bbox, osm_types, selector, conditions, out)
+        
+        return query_str, key
+
+    def get_grid_cell(self, lat: float, lon: float):
+        """
+        Returns the grid cell coordinates for a given latitude and longitude.
+        Each grid cell is 0.05°lat x 0.05°lon resolution in size.
+        """
+        lat_index = math.floor(lat / RESOLUTION)
+        lon_index = math.floor(lon / RESOLUTION)
+        return (lat_index, lon_index)
+
+
+    def get_bbox_from_grid_cell(self, lat_index: int, lon_index: int):
+        """
+        Returns the bounding box for a given grid cell index.
+        Each grid cell is resolution x resolution in size.
+
+        The bounding box is returned as (min_lat, min_lon, max_lat, max_lon).
+        """
+        # Calculate the southwest (min_lat, min_lon) corner of the bounding box
+        min_lat = round(lat_index * RESOLUTION, 2)
+        min_lon = round(lon_index * RESOLUTION, 2)
+
+        # Calculate the northeast (max_lat, max_lon) corner of the bounding box
+        max_lat = round((lat_index + 1) * RESOLUTION, 2)
+        max_lon = round((lon_index + 1) * RESOLUTION, 2)
+
+        return (min_lat, min_lon, max_lat, max_lon)
+
+
+
+    def get_overlapping_cells(self, query_bbox: tuple):
+        """
+        Returns a set of all grid cells that overlap with the given bounding box.
+        """
+        # Extract location from the query bbox
+        lat_min, lon_min, lat_max, lon_max = query_bbox
+
+        min_lat_cell, min_lon_cell = self.get_grid_cell(lat_min, lon_min)
+        max_lat_cell, max_lon_cell = self.get_grid_cell(lat_max, lon_max)
+
+        overlapping_cells = set()
+        for lat_idx in range(min_lat_cell, max_lat_cell + 1):
+            for lon_idx in range(min_lon_cell, max_lon_cell + 1):
+                overlapping_cells.add((lat_idx, lon_idx))
+        
+        return overlapping_cells
+
+
+    def combine_cached_data(self, cached_data_list):
+        """
+        Combines data from multiple cached responses into a single result.
+        """
+        combined_data = ET.Element("osm")
+        for cached_data in cached_data_list:
+            for element in cached_data:
+                combined_data.append(element)
+        return combined_data
+    
+
+    def fill_cache(self, query_str: str, cache_key) :
+        
+        # Prepare the data to be sent as POST request, encoded as bytes
+        data = urllib.parse.urlencode({'data': query_str}).encode('utf-8')
+
+        try:
+            # Create a Request object with the specified URL, data, and headers
+            request = urllib.request.Request(self.overpass_url, data=data, headers=self.headers)
+
+            # Send the request and read the response
+            with urllib.request.urlopen(request) as response:
+                # Read and decode the response
+                response_data = response.read().decode('utf-8')
+                root = ET.fromstring(response_data)
+
+                self.caching_strategy.set(cache_key, root)
+                self.logger.debug(f'Cache set')
+
+        except urllib.error.URLError as e:
+            raise ConnectionError(f"Error connecting to Overpass API: {e}") from e
+
+
+
+
+def get_base_info(elem: ET.Element, osm_type: OSM_TYPES, with_name=False) :
     """
     Extracts base information (coordinates, OSM ID, and optionally a name) from an OSM element.
 
@@ -169,3 +287,26 @@ def get_base_info(elem: ET.Element, osm_type: osm_types, with_name=False) :
         return osm_id, coords, name
     else :
         return osm_id, coords
+
+
+def fill_cache():
+
+    overpass = Overpass(caching_strategy='XML', cache_dir=OSM_CACHE_DIR)
+
+    with os.scandir(OSM_CACHE_DIR) as it:
+        for entry in it:
+            if entry.is_file() and entry.name.startswith('hollow_'):
+                
+                # Read the whole file content as a string
+                with open(entry.path, 'r') as f:
+                    xml_string = f.read()  
+
+                # Build the query and cache key from the hollow XML string
+                query_str, key = overpass.build_query_from_hollow(xml_string)
+                
+                # Fill the cache with the query and key
+                overpass.fill_cache(query_str, key)
+
+                # Now delete the file as the cache is filled
+                os.remove(entry.path)
+                
diff --git a/backend/src/parameters/landmark_parameters.yaml b/backend/src/parameters/landmark_parameters.yaml
index 159f19f..0cb8959 100644
--- a/backend/src/parameters/landmark_parameters.yaml
+++ b/backend/src/parameters/landmark_parameters.yaml
@@ -1,4 +1,4 @@
-city_bbox_side: 7500 #m
+max_bbox_side: 4000   #m
 radius_close_to: 50
 church_coeff: 0.55
 nature_coeff: 1.4
diff --git a/backend/src/structs/landmark.py b/backend/src/structs/landmark.py
index 50c9d78..ecb27ec 100644
--- a/backend/src/structs/landmark.py
+++ b/backend/src/structs/landmark.py
@@ -2,7 +2,7 @@
 
 from typing import Optional, Literal
 from uuid import uuid4, UUID
-from pydantic import BaseModel, Field
+from pydantic import BaseModel, ConfigDict, Field
 
 
 # Output to frontend
@@ -144,8 +144,4 @@ class Toilets(BaseModel) :
         """
         return f'Toilets @{self.location}'
 
-    class Config:
-        """
-        This allows us to easily convert the model to and from dictionaries
-        """
-        from_attributes = True
+    model_config = ConfigDict(from_attributes=True)
diff --git a/backend/src/tests/test_main.py b/backend/src/tests/test_main.py
index 8cbcdd3..80b7633 100644
--- a/backend/src/tests/test_main.py
+++ b/backend/src/tests/test_main.py
@@ -27,8 +27,8 @@ def test_turckheim(client, request):    # pylint: disable=redefined-outer-name
         "/trip/new",
         json={
             "preferences": {"sightseeing": {"type": "sightseeing", "score": 5},
-            "nature": {"type": "nature", "score": 5},
-            "shopping": {"type": "shopping", "score": 5},
+            "nature": {"type": "nature", "score": 0},
+            "shopping": {"type": "shopping", "score": 0},
             "max_time_minute": duration_minutes,
             "detour_tolerance_minute": 0},
             "start": [48.084588, 7.280405]
@@ -51,11 +51,11 @@ def test_turckheim(client, request):    # pylint: disable=redefined-outer-name
     assert response.status_code == 200  # check for successful planning
     assert isinstance(landmarks, list)  # check that the return type is a list
     assert len(landmarks) > 2           # check that there is something to visit
+    assert comp_time < 30, f"Computation time exceeded 30 seconds: {comp_time:.2f} seconds"
     assert duration_minutes*0.8 < result['total_time'], f"Trip too short: {result['total_time']} instead of {duration_minutes}"
     assert duration_minutes*1.2 > result['total_time'], f"Trip too long: {result['total_time']} instead of {duration_minutes}"
     # assert 2!= 3
 
-
 def test_bellecour(client, request) :   # pylint: disable=redefined-outer-name
     """
     Test n°2 : Custom test in Lyon centre to ensure proper decision making in crowded area.
diff --git a/backend/src/utils/cluster_manager.py b/backend/src/utils/cluster_manager.py
index 95d3f14..11ed333 100644
--- a/backend/src/utils/cluster_manager.py
+++ b/backend/src/utils/cluster_manager.py
@@ -10,6 +10,8 @@ from ..overpass.overpass import Overpass, get_base_info
 from ..structs.landmark import Landmark
 from .get_time_distance import get_distance
 from ..constants import OSM_CACHE_DIR
+from .utils import create_bbox
+
 
 
 # silence the overpass logger
@@ -81,7 +83,6 @@ class ClusterManager:
         # Setup the caching in the Overpass class.
         self.overpass = Overpass(caching_strategy='XML', cache_dir=OSM_CACHE_DIR)
 
-
         self.cluster_type = cluster_type
         if cluster_type == 'shopping' :
             osm_types = ['node']
@@ -95,16 +96,13 @@ class ClusterManager:
             raise NotImplementedError("Please choose only an available option for cluster detection")
 
         # Initialize the points for cluster detection
-        query = self.overpass.build_query(
-            area = bbox,
+        try:
+            result = self.overpass.send_query(
+            bbox = bbox,
             osm_types = osm_types,
             selector = sel,
             out = out
         )
-        self.logger.debug(f"Cluster query: {query}")
-
-        try:
-            result = self.overpass.send_query(query)
         except Exception as e:
             self.logger.error(f"Error fetching landmarks: {e}")
 
@@ -218,9 +216,8 @@ class ClusterManager:
         """
 
         # Define the bounding box for a given radius around the coordinates
-        lat, lon = cluster.centroid
-        bbox = (1000, lat, lon)
-
+        bbox = create_bbox(cluster.centroid, 1000)
+        
         # Query neighborhoods and shopping malls
         selectors = ['"place"~"^(suburb|neighborhood|neighbourhood|quarter|city_block)$"']
 
@@ -238,15 +235,12 @@ class ClusterManager:
         osm_types = ['node', 'way', 'relation']
 
         for sel in selectors :
-            query = self.overpass.build_query(
-                area = bbox,
-                osm_types = osm_types,
-                selector = sel,
-                out = 'ids center'
-            )
-
             try:
-                result = self.overpass.send_query(query)
+                result = self.overpass.send_query(bbox = bbox,
+                                                  osm_types = osm_types,
+                                                  selector = sel,
+                                                  out = 'ids center'
+                                                  )
             except Exception as e:
                 self.logger.error(f"Error fetching landmarks: {e}")
                 continue
diff --git a/backend/src/utils/landmarks_manager.py b/backend/src/utils/landmarks_manager.py
index 6aabace..26990f2 100644
--- a/backend/src/utils/landmarks_manager.py
+++ b/backend/src/utils/landmarks_manager.py
@@ -1,5 +1,6 @@
 """Module used to import data from OSM and arrange them in categories."""
 import logging
+import math as m
 import xml.etree.ElementTree as ET
 import yaml
 
@@ -9,12 +10,10 @@ from ..structs.landmark import Landmark
 from .take_most_important import take_most_important
 from .cluster_manager import ClusterManager
 from ..overpass.overpass import Overpass, get_base_info
+from .utils import create_bbox
 
 from ..constants import AMENITY_SELECTORS_PATH, LANDMARK_PARAMETERS_PATH, OPTIMIZER_PARAMETERS_PATH, OSM_CACHE_DIR
 
-# silence the overpass logger
-logging.getLogger('Overpass').setLevel(level=logging.CRITICAL)
-
 
 class LandmarkManager:
     """
@@ -37,8 +36,7 @@ class LandmarkManager:
 
         with LANDMARK_PARAMETERS_PATH.open('r') as f:
             parameters = yaml.safe_load(f)
-            self.max_bbox_side = parameters['city_bbox_side']
-            self.radius_close_to = parameters['radius_close_to']
+            self.max_bbox_side = parameters['max_bbox_side']
             self.church_coeff = parameters['church_coeff']
             self.nature_coeff = parameters['nature_coeff']
             self.overall_coeff = parameters['overall_coeff']
@@ -80,13 +78,13 @@ class LandmarkManager:
         """
         self.logger.debug('Starting to fetch landmarks...')
         max_walk_dist = int((preferences.max_time_minute/2)/60*self.walking_speed*1000/self.detour_factor)
-        reachable_bbox_side = min(max_walk_dist, self.max_bbox_side)
+        radius = min(max_walk_dist, int(self.max_bbox_side/2))
 
         # use set to avoid duplicates, this requires some __methods__ to be set in Landmark
         all_landmarks = set()
 
         # Create a bbox using the around technique, tuple of strings
-        bbox = tuple((min(2000, reachable_bbox_side/2), center_coordinates[0], center_coordinates[1]))
+        bbox = create_bbox(center_coordinates, radius)
 
         # list for sightseeing
         if preferences.sightseeing.score != 0:
@@ -193,17 +191,15 @@ class LandmarkManager:
                 query_conditions = []
                 osm_types.append('node')
 
-            query = self.overpass.build_query(
-                area = bbox,
+            # Send the overpass query
+            try:
+                result = self.overpass.send_query(
+                bbox = bbox,
                 osm_types = osm_types,
                 selector = sel,
                 conditions = query_conditions,        # except for nature....
                 out = 'center'
                 )
-            self.logger.debug(f"Query: {query}")
-
-            try:
-                result = self.overpass.send_query(query)
             except Exception as e:
                 self.logger.error(f"Error fetching landmarks: {e}")
                 continue
diff --git a/backend/src/utils/utils.py b/backend/src/utils/utils.py
new file mode 100644
index 0000000..23e9b52
--- /dev/null
+++ b/backend/src/utils/utils.py
@@ -0,0 +1,27 @@
+"""Various helper functions"""
+import math as m
+
+def create_bbox(coords: tuple[float, float], radius: int):
+    """
+    Create a bounding box around the given coordinates.
+
+    Args:
+        coords (tuple[float, float]): The latitude and longitude of the center of the bounding box.
+        radius (int): The half-side length of the bounding box in meters.
+
+    Returns:
+        tuple[float, float, float, float]: The minimum latitude, minimum longitude, maximum latitude, and maximum longitude
+                                            defining the bounding box.
+    """
+    # Earth's radius in meters
+    R = 6378137
+    lat, lon = coords
+    d_lat = radius / R
+    d_lon = radius / (R * m.cos(m.pi * lat / 180))
+
+    lat_min = lat - d_lat * 180 / m.pi
+    lat_max = lat + d_lat * 180 / m.pi
+    lon_min = lon - d_lon * 180 / m.pi
+    lon_max = lon + d_lon * 180 / m.pi
+
+    return (lat_min, lon_min, lat_max, lon_max)
\ No newline at end of file
