Google revealed on Tuesday its mass archive of graffiti art with an online gallery of more than 4,000 works from Rio de Janiero to Shanghai.

Paris-based Google Cultural Institute is behind the Street Art Project database. The images are provided by cultural institutions, often captured with Google's Street View cameras, but with strict guidelines that the institutions owns the rights to the art. (Artists can ask Google to remove images of their work.)

Some of the graffiti art in the database is now gone, including the 5Pointz murals in Queens, raising questions as to whether an ephemeral, and sometimes illegal, mode of art should be recorded.

"I'm not treating street art as anything different from what I would do with the Impressionist collection I'm getting on Art Project," said Amit Sood, director of the Google Cultural Institute. So far, the Google Art Project has about 460 museums worldwide providing images of their collections and Street Views of their galleries for online visitors to browse.