The Internet Archive is a San Francisco-based nonprofit digital library with the stated mission of "universal access to all knowledge". It provides free public access to collections of digitized materials, including web sites, software applications/games, music, movies/videos, moving images, and nearly three million public-domain books. As of May 2014, its collection topped 15 petabytes. In addition to its archiving function, the Archive is an activist organization, advocating for a free and open Internet.