American History in Video More than 5,000 hours of videos from commercial and governmental sources, like PBS, the BBC, and The History Channel. It also contains archival and public affairs footage.
Library of Congress http://www.loc.gov Prints, photographs, newspapers, and the American Memory Project .
New York Public Library Digital Gallery http://digitalcollections.nypl.org/
Brooklyn Public Library (includes Brooklyn Daily Eagle) http://www.brooklynpubliclibrary.org/
The Papers of John Jay http://www.columbia.edu/cu/lweb/digital/jay/
Hathi Trust rare books, documents, etc. including some NYPD annual reports. www.hathitrust.org
Internet Archives at https://archive.org/
NYC Department of Records Photo Gallery (at Municipal Archives). http://www.nyc.gov/html/records/html/archives/archives.shtml
Museum of the City of New York http://collections.mcny.org
U.S. Holocaust Memorial Museum http://www.ushmm.org/