OSM Then and Now
Explore OSM how it was in 2008 (left) and compare with how it is now (right). Use the slider to reveal more the one or the other. This is what a community of mappers can accomplish. If you enjoy using OpenStreetMap data, please consider a donation to the OpenStreetMap Foundation.
A thing by Martijn van Exel, source and instructions how to roll your own on Github. This site is currently broken on Safari, see this ticket.