What buildings were in the Fenway area of Boston in 1908? How about in Worcester in the 1870s? The state of Massachusetts has answers to these questions via its collections of real estate maps from the late 19th and early 20th centuries. All told, the State Library's collection includes over 200 atlases, covering 6,500 maps from 12 counties and more than 80 municipalities. Assisted by funds from the Institute of Museum and Library Services, this site brings together 167 of these volumes. Visitors to the site can examine all of the volumes either as PDF files or via Flickr. It's a rather engaging collection and visitors will thoroughly enjoy browsing through the genealogy of the Bay State's built environment.