The largest art museum in the world is in the city of Leningrad, in the Soviet Union. Most of the museum is in a building called the Winter Palace, but it also includes buildings nearby.
The museum contains 322 galleries and about three million works of art. If you wanted to see every work of art in the museum, you would have to walk about 15 miles!
The largest museum of any kind is the American Museum of Natural History, in New York City. The museum consists of 19 attached buildings and contains about 23 acres of floor space!