Tucked into the woods on a slope of Corcovado mountain is the International Museum of Naïve Art, the world's largest collection of folk art. There are more than 6,000 canvases by unschooled painters in the collection, which encompasses works from Europe, Africa, Australia, and the United States. A few gems are Brazilian Lia Mittarakis's exuberant Rio cityscapes and Paulo Pedro Leal's disturbingly childlike depictions of a death-squad killing. The building itself is a rather imposing and memorable colonial mansion set among tropical trees. At 561 Rua Cosme Velho; 55-21/ 2205-8612; museunaif.com.br.