There are more than 200 neighborhoods in Chicago, but there is no official list of the city's neighborhoods or their boundaries. Neighborhood names and identities have evolved over time due to real estate development and changing demographics. The City of Chicago is also divided into 77 community areas which were drawn by University of Chicago researchers in the late 1920s. Chicago's community areas are well-defined, generally contain multiple neighborhoods, and are less commonly used by city residents. More historical images of Chicago neighborhoods can be found in Explore Chicago Collections, a digital repository made available by Chicago Collections archives, libraries and other cultural institutions in the city.