By adding an historical map as an image overlay in Google Earth, you can get a sense of how a city has changed over time. This video is made from a series of screenshots of Google Earth with the historical map overlay at various levels of transparency and zoom. I was interested in seeing how the historic district (commonly called Old Sacramento) has changed over time. In particular, I wanted to know where the notorious Sutter Lake used to be. By aligning the historic map to the contemporary street grid, you can see not only the previous location of Sutter Lake, but also the American River’s former channel and riverbed.
Source: Map of the City of Sacramento, the Capital of California. By J.R. Ray, City Surveyor, 1873. David Rumsey Map Collection.