Google has a new map for you to play with. The 1893-96 Ordnance Survey map of London — recently released by the National Library of Scotland — has now been superimposed over a modern Google map. It's an extremely detailed map that shows the locations of pubs, drinking fountains, parish boundaries, post offices and a ton of other stuff. Best of all, a slider bar allows you to morph between old and modern maps, to get a better idea of how the streets have changed.
Here's the view around Londonist Towers. Had our company somehow been functioning 120 years ago, we could have enjoyed such local amenities as a free library, a tram line to Spitalfields Market or the Tabernacle Square urinal, all while basking in the aromas of the local vinegar factory. 
The OS chart is one of several historic London maps available in this format on Google's Maps Gallery.
