We've seen heatmaps before, cue the world's tourism hotspots based on Panoramio photos from Estonia-based Bluemoon Interactive, and some are pretty cool (no pun intended).
Now, Sightsmap reckons it has taken them to a new level by allowing users to not only view the photos but also link out to further information via Wikipedia, Foursquare and Tripadvisor.
Street level heatmaps are available for about 15,000 of the most popular places in the world and the popularity of places is based on the pictures and information from Foursquare, Wikipedia and Google Places.
The service also enables users to create and share their own maps and trip itineraries.
Anyway, just goes to show how mash-ups are evolving.
Sightsmap was created by Tanel Tammet, a professor at Tallinn University of Technology.