Already the world's seventh-busiest museum (with about 5 million visitors each year), the Tate Modern didn't need any extra selling points. But it now has 222,813 square feet of them in a 10-story wing that opened in June promising lots of room for interactive art. There's also fantastic 360-views of the River Thames, St. Paul's Cathedral, and more of London's gorgeous skyline from the top-floor terrace. The new building sits above The Tanks, which is a one-of-a-kind gallery space focused on live art, film, and other installations.
Right now, art fans are checking out the largest-ever exhibition of Georgia O'Keeffe's flower paintings, charcoals, and photographs, on view through October. For tickets and more information about the museum, visit tate.org.uk.