The Great Fire of London destroyed the vast majority of the city in 1666. Of course, the river, the streets, and the property lines still remained, and the residents started rebuilding. But most city maps were gone, so work began on a new map.
The Morgan Map of 1682 was the first to show the whole of the City of London after the fire. Produced by William Morgan and his dedicated team of Surveyors and Cartographers it took 6 years to produce, and displayed a brighter perspective on city life for a population still mourning their loved ones, possessions, and homes.
Now the Morgan Map has been overlaid with aerial views of the city at the London Time Machine. A "spyglass" shows the city as it is today. You can move the spyglass around, zoom in and out, and pull the spyglass off the map the see how much bigger London is today. However, if you go too far, you can lose the older map and have to reload. Check it out here. -via Metafilter