This week I found the most amazing Victorian map of London online. Virtually every sheet of the  Ordnance Survey's 1893-6 "Five Feet to the Mile" scale series has been painstakingly layered on top of a modern Google map. 

The detail at this scale is really amazing, you can see the layouts of individual buildings and even recognisable trees. The online version is superior to the original printed sheets as you easily zoom in, search, and move around the map. …