The map shows all the filming locations of the movies which have won Best Picture at the Academy Awards, from 1927 to 2014. Markers are stored in a javascript object, and MarkerClusterer and Overlapping Marker Spiderfier are used jointly to group the large number of markers.
Bootstrap has been used for the map design, so it is responsive on any device.
(This version includes a nav bar from my site - I've chosen to leave it on as it was a challenge for me to make the map responsive without overlapping the nav bar - so this help someone with the same problem).