diff --git a/maps.py b/maps.py
index 27d9e4586..c4ecac990 100644
--- a/maps.py
+++ b/maps.py
@@ -215,7 +215,9 @@ def geocoords_from_map_link(url: str,
 
 def html_open_street_map(url: str,
                          bounding_box_degrees: float,
-                         translate: {}) -> str:
+                         translate: {},
+                         width: str = "725",
+                         height: str = "650") -> str:
     """Returns embed html for an OSM link
     """
     osm_domain = 'openstreetmap.org'
@@ -228,7 +230,8 @@ def html_open_street_map(url: str,
         return ''
 
     html_str = \
-        '<iframe width="725" height="650" frameborder="0" ' + \
+        '<iframe width="' + width + '" height="' + height + \
+        '" frameborder="0" ' + \
         'scrolling="no" marginheight="0" marginwidth="0" ' + \
         'src="https://www.' + osm_domain + '/export/embed.html?' + \
         'bbox=' + str(longitude - bounding_box_degrees) + \
diff --git a/webapp_calendar.py b/webapp_calendar.py
index a6caf240d..368cd83fa 100644
--- a/webapp_calendar.py
+++ b/webapp_calendar.py
@@ -193,7 +193,8 @@ def _html_calendar_day(person_cache: {}, css_cache: {}, translate: {},
                             event_map = \
                                 html_open_street_map(event_place,
                                                      bounding_box_degrees,
-                                                     translate)
+                                                     translate,
+                                                     '30vw', '30vw')
                             if event_map:
                                 event_place = event_map