Flickr Commons
flickr.com/commons
A collaborative project where public institutions share photographs from their collections on Flickr, making millions of historical images freely accessible.
Why it is useful
Brings together photo archives from the Library of Congress, NASA, the Smithsonian, and hundreds of museums and libraries into a single browsable platform. The tagging and commenting community helps surface contextual information that the originating institutions often don't provide. For visual researchers and designers, it is one of the most browsable sources of high-quality historical photography.