Wikimapia is a satellite navigation tool that combines Google Maps with a wiki. By zooming in or out on the map, a user can view and add notes to various points on the map describing people, places or events. Other media, such as images, can be added to the notes. For example, I could put a note next to the Ontario Legislature in Toronto, describing the building, it’s history and notable political rallies held there on certain dates, also providing accompanying pictures and links to related external content. The tagline for Wikimapia is ‘let’s describe the whole world!’

http://wikimapia.org