diff --git a/site/src/components/Explore.svelte b/site/src/components/Explore.svelte
index 4b4dd77..805aa1a 100644
--- a/site/src/components/Explore.svelte
+++ b/site/src/components/Explore.svelte
@@ -22,10 +22,11 @@
   let dateFrom = '';
   let dateTo = '';
   let selectedYear: string | null = null;
+  let selectedMonth: number | null = null;
 
   // View
-  let viewMode: 'lines' | 'heatmap' = 'lines';
-  let heatmapMode: 'global' | 'bytype' = 'global';
+  let viewMode: 'lines' | 'heatmap' = 'heatmap';
+  let heatmapMode: 'global' | 'bytype' = 'bytype';
 
   // Tile layers — same as planner
   const TILES: Record<string, { tiles: string[]; attribution: string; label: string }> = {
@@ -83,26 +84,49 @@
   function clearAllTypes()  { selectedTypes = new Set(); }
 
   function setYear(y: string) {
-    if (selectedYear === y) { selectedYear = null; dateFrom = ''; dateTo = ''; return; }
+    if (selectedYear === y) { selectedYear = null; selectedMonth = null; dateFrom = ''; dateTo = ''; return; }
     selectedYear = y;
+    selectedMonth = null;
     dateFrom = `${y}-01-01`;
     dateTo   = `${y}-12-31`;
   }
 
   function setMonth(m: number) { // m: 1-12
     if (!selectedYear) return;
+    selectedMonth = m;
     const mm  = String(m).padStart(2, '0');
     const last = new Date(+selectedYear, m, 0).getDate();
     dateFrom = `${selectedYear}-${mm}-01`;
     dateTo   = `${selectedYear}-${mm}-${String(last).padStart(2,'0')}`;
   }
 
-  function clearDates() { dateFrom = ''; dateTo = ''; selectedYear = null; }
+  function clearMonth() {
+    if (!selectedYear) return;
+    selectedMonth = null;
+    dateFrom = `${selectedYear}-01-01`;
+    dateTo   = `${selectedYear}-12-31`;
+  }
+
+  function clearDates() { dateFrom = ''; dateTo = ''; selectedYear = null; selectedMonth = null; }
 
   // ── Map ────────────────────────────────────────────────────────────────────
 
+  let _bbox: { w: number; e: number; s: number; n: number } | null = null;
+
+  function _getBbox() {
+    if (!map) return null;
+    const b = map.getBounds();
+    return { w: b.getWest(), e: b.getEast(), s: b.getSouth(), n: b.getNorth() };
+  }
+
+  function _inBbox(lng: number, lat: number): boolean {
+    if (!_bbox) return true;
+    return lng >= _bbox.w && lng <= _bbox.e && lat >= _bbox.s && lat <= _bbox.n;
+  }
+
   function _linesGeoJSON(ts: Track[]) {
-    return { type: 'FeatureCollection', features: ts.map(t => ({
+    const visible = _bbox ? ts.filter(t => t.coords.some(([lng, lat]) => _inBbox(lng, lat))) : ts;
+    return { type: 'FeatureCollection', features: visible.map(t => ({
       type: 'Feature',
       geometry: { type: 'LineString', coordinates: t.coords },
       properties: { type: t.type },
@@ -113,7 +137,8 @@
     const features: any[] = [];
     for (const t of ts)
       for (const [lng, lat] of t.coords)
-        features.push({ type: 'Feature', geometry: { type: 'Point', coordinates: [lng, lat] }, properties: { type: t.type } });
+        if (_inBbox(lng, lat))
+          features.push({ type: 'Feature', geometry: { type: 'Point', coordinates: [lng, lat] }, properties: { type: t.type } });
     return { type: 'FeatureCollection', features };
   }
 
@@ -203,9 +228,15 @@
       }
 
       mapReady = true;
+      _bbox = _getBbox();
       _updateMap(tracks, viewMode, heatmapMode);
       _fitBounds(tracks);
     });
+
+    map.on('moveend', () => {
+      _bbox = _getBbox();
+      if (mapReady) _updateMap(filteredTracks, viewMode, heatmapMode);
+    });
   });
 
   onDestroy(() => { if (map) map.remove(); });
@@ -261,9 +292,10 @@
       </div>
       {#if selectedYear}
         <div class="pills month-pills">
+          <button class="pill small" class:active={selectedMonth === null} onclick={clearMonth}>All</button>
           {#each MONTHS as m, i}
             <button class="pill small"
-              class:active={dateFrom === `${selectedYear}-${String(i+1).padStart(2,'0')}-01`}
+              class:active={selectedMonth === i + 1}
               onclick={() => setMonth(i + 1)}>{m}</button>
           {/each}
         </div>