Vector Map is an amazing map of the world, complete with 3d extruded buildings and roads with animated traffic. The screenshot above doesn't do this map justice and you really need to view the map yourself in a WebGL enabled browser.
The map was built with Mapzen's Tangram mapping engine. Tangram is a library for creating 2D & 3D maps with WebGL. The Vector Map includes Tangram's extruded 3d building footprints and adds animated traffic to the map's roads.