If you're a fan of New York City history you're going to want to explore this genuinely awesome site from New York City's Department of Transportation. The DOT's NYCityMap allows you to search for an address, place of interest, place of interest, borough block lot, intersection, community district, city council district, or zip code. Once you make your selection you'll be presented with a fairly conventional aerial view. You might ask what's the big deal? Select the little camera icon at the top of the map and you will find out. This humble looking tool gives you the option of overlaying an aerial view of your area of interest in 2008, 2006, and 1924! So, go look for the Empire State Building, move back to 1924 and see it disappear (the Empire State building was built between 1929 and 1931). Enjoy!