This museum presents the work of today's most cutting-edge artists—starting with the artistry of the building itself, the first freestanding American museum designed by a woman, Iraq-born architect Zaha Hadid. When it was completed in 2003, New York Times architecture critic Herbert Muschamp famously called it "the most important building completed since the end of the Cold War." Exhibits showcase photography, film, performance art, and even art that primarily uses sound. There are no permanent installations, save for the sixth-floor UnMuseum, a 7,400-square-foot wonderland for kids and adults; one of the more popular attractions is the robot-tree, which responds to your presence by raising or lowering its branches. The youngest children will love the Leaf Lounge, where they take off their shoes and roll about in more than 450 hand-made leaves. The stuffed leaves are five times the actual size of their sylvan cousins and are spread across a bed of bouncy foam.