diff --git a/buildings-start_date.json b/buildings-start_date.json
new file mode 100644
index 0000000..04a0d67
--- /dev/null
+++ b/buildings-start_date.json
@@ -0,0 +1,120 @@
+{
+    "type": "overpass",
+    "name": {
+        "en": "Buildings",
+        "de": "Gebäude"
+    },
+    "query": {
+        "16": [
+            "(",
+            "  way[building];",
+            "  relation[building];",
+            ")"
+        ]
+    },
+    "feature": {
+        "pre": [
+            "{% if tags.start_date %}",
+            "  {% set value = tags.start_date|osmParseDate %}",
+            "  {% if value and value[0] and value[1] %}",
+            "    {% set value = (value[1] - value[0]) / 2 + value[0] %}",
+            "  {% elseif value and value[0] %}",
+            "    {% set value = value[0] %}",
+            "  {% elseif value and value[1] %}",
+            "    {% set value = value[1] %}",
+            "  {% else %}",
+            "    {% set value = 'error' %}",
+            "  {% endif %}",
+            "",
+            "  {% if value == 'error' %}",
+            "    {% set color = '#ff0000' %}",
+            "  {% elseif value < 1500 %}",
+            "    {% set color = '#0000ff' %}",
+            "  {% elseif value < 1900 %}",
+            "    {% set color = colorInterpolate([ '#0000ff', '#ff00ff' ], (value - 1500.0) / 400) %}",
+            "  {% elseif value < 2000 %}",
+            "    {% set color = colorInterpolate([ '#ff00ff', '#ffff00' ], (value - 1900.0) / 100) %}",
+            "  {% else %}",
+            "    {% set color = colorInterpolate([ '#ffff00', '#00ff00' ], (value - 2000.0) / 50) %}",
+            "  {% endif %}",
+            "{% else %}",
+            "{% set color = '#000000' %}",
+            "{% endif %}"
+        ],
+        "description": [
+            "{% if tags.start_date %}",
+            "{{ tags.start_date }}",
+            "{% endif %}"
+        ],
+        "markerSign": null,
+        "listMarkerSymbol": "polygon",
+        "priority": [
+            "{% set p = 100 %}",
+            "{% if tags.start_date %}{% set p = p - 20 %}{% endif %}",
+            "{% if tags.name %}{% set p = p - 10 %}{% endif %}",
+            "{% if tags.amenity %}{% set p = p - 1 %}{% endif %}",
+            "{% if tags.historic %}{% set p = p - 1 %}{% endif %}",
+            "{% if tags.culture %}{% set p = p - 1 %}{% endif %}",
+            "{% if tags.highway %}{% set p = p - 1 %}{% endif %}",
+            "{% if tags.railway %}{% set p = p - 1 %}{% endif %}",
+            "{% if tags.aeroway %}{% set p = p - 1 %}{% endif %}",
+            "{% if tags.amenity %}{% set p = p - 1 %}{% endif %}",
+            "{% if tags.tourism %}{% set p = p - 1 %}{% endif %}",
+            "{{ p }}"
+        ],
+        "style": {
+            "weight": "1",
+            "color": "#000000",
+            "fillColor": "{{ color }}",
+            "fillOpacity": "0.8"
+        }
+    },
+    "info": [
+        "<table>",
+        "  <tr>",
+        "    <td>{{ markerPolygon(evaluate({ \"building\": \"yes\", \"start_date\": \"1400\" }))|raw }}</td>",
+        "    <td>&lt;1500</td>",
+        "  </tr>",
+        "  <tr>",
+        "    <td>{{ markerPolygon(evaluate({ \"building\": \"yes\", \"start_date\": \"1500\" }))|raw }}</td>",
+        "    <td>1500</td>",
+        "  </tr>",
+        "  <tr>",
+        "    <td>{{ markerPolygon(evaluate({ \"building\": \"yes\", \"start_date\": \"1600\" }))|raw }}</td>",
+        "    <td>1600</td>",
+        "  </tr>",
+        "  <tr>",
+        "    <td>{{ markerPolygon(evaluate({ \"building\": \"yes\", \"start_date\": \"1700\" }))|raw }}</td>",
+        "    <td>1700</td>",
+        "  </tr>",
+        "  <tr>",
+        "    <td>{{ markerPolygon(evaluate({ \"building\": \"yes\", \"start_date\": \"1800\" }))|raw }}</td>",
+        "    <td>1800</td>",
+        "  </tr>",
+        "  <tr>",
+        "    <td>{{ markerPolygon(evaluate({ \"building\": \"yes\", \"start_date\": \"1900\" }))|raw }}</td>",
+        "    <td>1900</td>",
+        "  </tr>",
+        "  <tr>",
+        "    <td>{{ markerPolygon(evaluate({ \"building\": \"yes\", \"start_date\": \"1950\" }))|raw }}</td>",
+        "    <td>1950</td>",
+        "  </tr>",
+        "  <tr>",
+        "    <td>{{ markerPolygon(evaluate({ \"building\": \"yes\", \"start_date\": \"2000\" }))|raw }}</td>",
+        "    <td>2000</td>",
+        "  </tr>",
+        "  <tr>",
+        "    <td>{{ markerPolygon(evaluate({ \"building\": \"yes\", \"start_date\": \"2020\" }))|raw }}</td>",
+        "    <td>2020</td>",
+        "  </tr>",
+        "  <tr>",
+        "    <td>{{ markerPolygon(evaluate({ \"building\": \"yes\", \"start_date\": \"xxx\" }))|raw }}</td>",
+        "    <td>unparseable start_date</td>",
+        "  </tr>",
+        "  <tr>",
+        "    <td>{{ markerPolygon(evaluate({ \"building\": \"yes\" }))|raw }}</td>",
+        "    <td>no start_date</td>",
+        "  </tr>",
+        "</table>"
+    ]
+}
diff --git a/buildings.json b/buildings.json
index 0d77826..cae67fd 100644
--- a/buildings.json
+++ b/buildings.json
@@ -12,6 +12,9 @@
         },
         {
             "id": "buildings-height"
+        },
+        {
+            "id": "buildings-start_date"
         }
     ]
 }