Louvre Museum
http://www.louvre.fr/en
Metropolitan Museum of Art
http://www.metmuseum.org
National Gallery of Art (DC)
http://www.nga.gov/content/ngaweb.html
National Gallery of Art (London)
https://www.nationalgallery.org.uk
Museum of Modern Art
http://www.moma.org
Tate Galleries
http://www.tate.org.uk
Christies
http://www.christies.com
Sotheby's
http://www.sothebys.com/en.html
Wikiart
http://www.wikiart.org
Google Arts and Culture
https://www.google.com/culturalinstitute/beta/
The Art Story
http://www.theartstory.org
