National Archive

https://www.archives.gov

The Met

https://www.metmuseum.org

National Gallery of Art

https://www.nga.gov/

Google Arts and Culture

https://www.google.com/culturalinstitute/beta/

Library of Congress

https://www.loc.gov/

Presidential Libraries

The J. Paul Getty

http://www.getty.edu/museum/

The Broad

www.broad.org