May 19, 2010 Find Your Ancestor's Building in New York City
An interesting city government web site will provide a map and even aerial photographs showing the location of the building where you or your ancestors lived in New York City. You key in a specific address and the result is a map of the area showing an outline of every building.
After locating a building, click "Show Additional Information" and data will be provided such as lot frontage, depth and area; year built; gross floor area; number of residential units; and whether it has been designated as a Landmark building.
If you click on the camera icon you get a slider with years on it, and get aerial photos taken in those years.