diff --git a/dve.css b/dve.css
index fb654cd..5876ad9 100644
--- a/dve.css
+++ b/dve.css
@@ -6,13 +6,33 @@ html, body {
   font-family: sans-serif;
 }
 #container {
-  display: flex;
+  display: grid;
   height: 100vh;
   width: 100vw;
 }
+#container[data-count="2"] {
+  grid-template-columns: repeat(2, 1fr);
+  grid-template-rows: 1fr;
+}
+#container[data-count="4"] {
+  grid-template-columns: repeat(2, 1fr);
+  grid-template-rows: repeat(2, 1fr);
+}
+#container[data-count="6"] {
+  grid-template-columns: repeat(3, 1fr);
+  grid-template-rows: repeat(2, 1fr);
+}
+#container[data-count="9"] {
+  grid-template-columns: repeat(3, 1fr);
+  grid-template-rows: repeat(3, 1fr);
+}
 .map-wrapper {
-  flex: 1;
   position: relative;
+  min-width: 0;
+  min-height: 0;
+}
+.map-wrapper.hidden {
+  display: none;
 }
 .map {
   height: 100%;
@@ -28,3 +48,36 @@ html, body {
   border-radius: 4px;
   font-size: 14px;
 }
+.layout-selector {
+  position: fixed;
+  top: auto;
+  bottom: 10px;
+}
+
+.crosshair {
+  position: absolute;
+  display: none;
+  width: 24px;
+  height: 24px;
+  z-index: 999;
+  pointer-events: none;
+  transform: translate(-50%, -50%);
+}
+.crosshair::before,
+.crosshair::after {
+  content: "";
+  position: absolute;
+  background: #000;
+}
+.crosshair::before {
+  left: 11px;
+  top: 0;
+  width: 2px;
+  height: 24px;
+}
+.crosshair::after {
+  left: 0;
+  top: 11px;
+  width: 24px;
+  height: 2px;
+}
diff --git a/dve.js b/dve.js
index 5f874af..936bbcb 100644
--- a/dve.js
+++ b/dve.js
@@ -6,10 +6,18 @@ const json_files = [
 
 const center = [50.08804, 14.42076];
 const zoom = 14;
+const mapCounts = [2, 4, 6, 9];
 
 let syncing = false;
+let urlUpdateTimer = null;
+let activeMouseMap = null;
+let activeMousePoint = null;
+let activeMouseLatLng = null;
 
 let TILE_SERVERS = [];
+let maps = [];
+let layers = [];
+let crosshairs = [];
 
 function fillDropdown(select) {
   for (const name in TILE_SERVERS) {
@@ -20,11 +28,85 @@ function fillDropdown(select) {
   }
 }
 
-function sync(source, target) {
+function readUrlState() {
+  const state = {
+    center,
+    zoom,
+    count: 2,
+    layers: []
+  };
+
+  const match = window.location.hash.match(/^#map=([0-9.]+)\/(-?[0-9.]+)\/(-?[0-9.]+)/);
+
+  if (match) {
+    const z = parseFloat(match[1]);
+    const lat = parseFloat(match[2]);
+    const lng = parseFloat(match[3]);
+
+    if (Number.isFinite(lat) && Number.isFinite(lng) && Number.isFinite(z)) {
+      state.center = [lat, lng];
+      state.zoom = z;
+    }
+  }
+
+  const params = new URLSearchParams(window.location.hash.replace(/^#map=[^&]*/, ""));
+  const count = parseInt(params.get("count"), 10);
+
+  if (mapCounts.includes(count)) {
+    state.count = count;
+  }
+
+  for (let i = 1; i <= state.count; i++) {
+    const layer = params.get("layer" + i);
+
+    if (layer) state.layers.push(layer);
+  }
+
+  return state;
+}
+
+function getSelectedLayers(count) {
+  const selected = [];
+
+  for (let i = 1; i <= count; i++) {
+    const select = document.getElementById("select" + i);
+    if (select && select.value) selected.push(select.value);
+  }
+
+  return selected;
+}
+
+function writeUrlState(map) {
+  if (urlUpdateTimer) clearTimeout(urlUpdateTimer);
+
+  urlUpdateTimer = setTimeout(() => {
+    const c = map.getCenter();
+    const count = parseInt(document.getElementById("mapCountSelector").value, 10);
+    let hash = "#map=" + map.getZoom() + "/" + c.lat.toFixed(5) + "/" + c.lng.toFixed(5);
+
+    hash += "&count=" + count;
+
+    const selected = getSelectedLayers(count);
+    selected.forEach((name, index) => {
+      hash += "&layer" + (index + 1) + "=" + encodeURIComponent(name);
+    });
+
+    history.replaceState(null, "", hash);
+  }, 100);
+}
+
+function sync(source) {
   if (syncing) return;
   syncing = true;
-  target.setView(source.getCenter(), source.getZoom(), { animate: false });
+  maps.forEach(target => {
+    if (target !== source) {
+      target.setView(source.getCenter(), source.getZoom(), { animate: false });
+    }
+  });
   syncing = false;
+
+  writeUrlState(source);
+  updateCrosshairs();
 }
 
 function setLayer(map, config, currentLayer) {
@@ -50,41 +132,142 @@ function setLayer(map, config, currentLayer) {
   }
 }
 
+function fillMapCountDropdown(select) {
+  select.innerHTML = "";
+
+  mapCounts.forEach(count => {
+    const opt = document.createElement("option");
+    opt.value = count;
+    opt.textContent = count + (count === 2 || count === 4 ? " mapy" : " map");
+    select.appendChild(opt);
+  });
+}
+
+function setMapCount(count) {
+  const container = document.getElementById("container");
+  container.dataset.count = count;
+
+  for (let i = 1; i <= maps.length; i++) {
+    const wrapper = document.getElementById("map" + i).parentElement;
+    wrapper.classList.toggle("hidden", i > count);
+  }
+
+  hideCrosshairs();
+
+  setTimeout(() => {
+    maps.forEach((map, index) => {
+      if (index < count) map.invalidateSize(false);
+    });
+  }, 0);
+}
+
+function isVisibleMap(map) {
+  return !map.getContainer().parentElement.classList.contains("hidden");
+}
+
+function createCrosshair(map) {
+  const crosshair = document.createElement("div");
+  crosshair.className = "crosshair";
+  map.getContainer().parentElement.appendChild(crosshair);
+  return crosshair;
+}
+
+function hideCrosshairs() {
+  activeMouseMap = null;
+  activeMousePoint = null;
+  activeMouseLatLng = null;
+
+  crosshairs.forEach(crosshair => {
+    crosshair.style.display = "none";
+  });
+}
+
+function updateCrosshairs() {
+  if (!activeMouseMap || !activeMousePoint || !isVisibleMap(activeMouseMap)) return;
+
+  activeMouseLatLng = activeMouseMap.containerPointToLatLng(activeMousePoint);
+
+  maps.forEach((map, index) => {
+    const crosshair = crosshairs[index];
+
+    if (map === activeMouseMap || !isVisibleMap(map)) {
+      crosshair.style.display = "none";
+      return;
+    }
+
+    const point = map.latLngToContainerPoint(activeMouseLatLng);
+    const size = map.getSize();
+
+    if (point.x < 0 || point.y < 0 || point.x > size.x || point.y > size.y) {
+      crosshair.style.display = "none";
+      return;
+    }
+
+    crosshair.style.left = point.x + "px";
+    crosshair.style.top = point.y + "px";
+    crosshair.style.display = "block";
+  });
+}
+
+function initCrosshair(map) {
+  const container = map.getContainer();
+
+  map.on("mousemove", e => {
+    activeMouseMap = map;
+    activeMousePoint = map.mouseEventToContainerPoint(e.originalEvent);
+    activeMouseLatLng = e.latlng;
+    updateCrosshairs();
+  });
+
+  map.on("mouseout", e => {
+    if (!container.contains(e.originalEvent.relatedTarget)) hideCrosshairs();
+  });
+
+  map.on("move", () => updateCrosshairs());
+  map.on("zoom", () => updateCrosshairs());
+}
+
 function init() {
-  fillDropdown(document.getElementById("select1"));
-  fillDropdown(document.getElementById("select2"));
+  const urlState = readUrlState();
+  const mapCountSelector = document.getElementById("mapCountSelector");
+  fillMapCountDropdown(mapCountSelector);
 
-  // Create maps
-  const map1 = L.map("map1", { center, zoom, zoomControl: false });
-  const map2 = L.map("map2", { center, zoom, zoomControl: false });
+  for (let i = 1; i <= 9; i++) {
+    const select = document.getElementById("select" + i);
+    fillDropdown(select);
 
-  map1.on("move", () => sync(map1, map2));
-  map2.on("move", () => sync(map2, map1));
+    if (urlState.layers[i - 1] && TILE_SERVERS[urlState.layers[i - 1]]) {
+      select.value = urlState.layers[i - 1];
+    }
 
-  map1.on("zoom", () => sync(map1, map2));
-  map2.on("zoom", () => sync(map2, map1));
+    const map = L.map("map" + i, { center: urlState.center, zoom: urlState.zoom, zoomControl: false });
+    map.on("move", () => sync(map));
+    map.on("zoom", () => sync(map));
 
-  L.control.zoom({ position: "topright" }).addTo(map1);
-  L.control.zoom({ position: "topright" }).addTo(map2);
+    L.control.zoom({ position: "topright" }).addTo(map);
 
-  // Active tile layers
-  let layer1 = null;
-  let layer2 = null;
+    maps.push(map);
+    layers.push(null);
+    crosshairs.push(createCrosshair(map));
+    initCrosshair(map);
 
-  // Initialize with first server
-  layer1 = setLayer(map1, TILE_SERVERS[document.getElementById("select1").value], layer1);
-  layer2 = setLayer(map2, TILE_SERVERS[document.getElementById("select2").value], layer2);
+    layers[i - 1] = setLayer(map, TILE_SERVERS[select.value], layers[i - 1]);
 
-  // Dropdown change handlers
-  document.getElementById("select1").addEventListener("change", e => {
-    const key = e.target.value;   
-    layer1 = setLayer(map1, TILE_SERVERS[key], layer1);      
+    select.addEventListener("change", e => {
+      const key = e.target.value;
+      layers[i - 1] = setLayer(map, TILE_SERVERS[key], layers[i - 1]);
+      writeUrlState(map);
+    });
+  }
+
+  mapCountSelector.value = urlState.count;
+  mapCountSelector.addEventListener("change", e => {
+    setMapCount(parseInt(e.target.value, 10));
+    writeUrlState(maps[0]);
   });
 
-  document.getElementById("select2").addEventListener("change", e => {
-    const key = e.target.value;
-    layer2 = setLayer(map2, TILE_SERVERS[key], layer2);
-  });
+  setMapCount(parseInt(mapCountSelector.value, 10));
+  writeUrlState(maps[0]);
 }
 
 async function loadTileConfigs(json_files) {
diff --git a/index.html b/index.html
index df18083..5f1763b 100644
--- a/index.html
+++ b/index.html
@@ -29,7 +29,7 @@
 
 </head>
 <body>
-  <div id="container">
+  <div id="container" data-count="2">
     <div class="map-wrapper">
       <select id="select1" class="selector"></select>
       <div id="map1" class="map"></div>
@@ -38,6 +38,40 @@
       <select id="select2" class="selector"></select>
       <div id="map2" class="map"></div>
     </div>
+    <div class="map-wrapper hidden">
+      <select id="select3" class="selector"></select>
+      <div id="map3" class="map"></div>
+    </div>
+    <div class="map-wrapper hidden">
+      <select id="select4" class="selector"></select>
+      <div id="map4" class="map"></div>
+    </div>
+    <div class="map-wrapper hidden">
+      <select id="select5" class="selector"></select>
+      <div id="map5" class="map"></div>
+    </div>
+    <div class="map-wrapper hidden">
+      <select id="select6" class="selector"></select>
+      <div id="map6" class="map"></div>
+    </div>
+    <div class="map-wrapper hidden">
+      <select id="select7" class="selector"></select>
+      <div id="map7" class="map"></div>
+    </div>
+    <div class="map-wrapper hidden">
+      <select id="select8" class="selector"></select>
+      <div id="map8" class="map"></div>
+    </div>
+    <div class="map-wrapper hidden">
+      <select id="select9" class="selector"></select>
+      <div id="map9" class="map"></div>
+    </div>
   </div>
+  <select id="mapCountSelector" class="selector layout-selector">
+    <option value="2">2 mapy</option>
+    <option value="4">4 mapy</option>
+    <option value="6">6 map</option>
+    <option value="9">9 map</option>
+  </select>
 </body>
 </html>