Cool San Francisco Maps

I heard this story on NPR the other day about maps and thought it sounded cool. Folks have found old fire insurance maps from 1905 and put them into digital format with the idea of overlaying them with current city topography. It's amazing to see what was where (I found my current block used to have a billiards factory and some hotels as well as a stable). Worth checking out if you're into maps and random cartography fun!