Below are three snapshots to get an ideea about the interface. One is taken at country level, the next at continent level and the last shows the whole world.
Easily compare Google Maps, OpenStreetMaps, Bing Maps and Nokia Here Maps.
Click a map and start zooming and panning. The other maps will follow.
Drag the red square to quickly switch between maps.
Drag the red square all the way to the opossite corner to reveal the whole map's interface. Like this, you can manipulate the map and change between terrain, satellite etc.
make Firefox get along with Google Maps (check this if you experience lag while dragging Google Map or OSM).
Click arrows bellow to switch maps positions.