Google Maps is great, but it has one glaring problem: it only provides information for the present day. For the avid time traveler, it's essentially useless.
What good would a map of 1985 Hill Valley have been to Marty McFly trying to find his way around in 1955, when everything except the town square and high school were completely different? Back then, the mall was just a farm run by an old man with a crazy idea about breeding pine trees.
Old western times? Forget about it.
Enter: Pastmapper, designer Brad Thompson's bold attempt at dragging Google Maps back in time. Thompson describes his site as, "a new platform for organizing data using the visual language of online maps to describe the world of the past."
To start, he's taken downtown San Francisco circa 1853 and, using a U.S. Coast Survey map from the David Rumsey Historical Map Collection along with directory information from A.W. Morgan & Company's San Francisco City Directory, created a visual representation of what the city looked like during the heyday of the gold rush.
"A lot has changed in the last 158 years," writes Thompson in a blog post explaining the project. "Hills have been leveled, coastlines have expanded, and points of interest have been renamed. A staggering number of streets have been closed, opened, renamed, or widened. Building numbering in San Francisco changed completely in 1861, so even the street addresses don't match their 2011 counterparts."
Looking at the map, you can see trends like how Clay Street was the medical center of its time with doctor and surgeon/dentist offices lining either side.
Thompson's ultimate, wildly ambitious plan is to expand Pastmapper to every city at every time in history for which information is available. "Imagine being able to look back in time at your neighborhood, to see how businesses and landmarks developed," he writes. "Your local cafe might have been a saloon, or a speakeasy, or a soda fountain--or all three, at different points in time."