Okavango flow
© Russell Patterson/500px/Getty Images
From the Nile to the Mississippi to the Mekong, most famous river deltas empty into an ocean. The Okavango Delta, though its splitting streams still take a familiar triangle shape, is instead ultimately swallowed by the deep, dry Kalahari desert. But before reaching their endorheic endpoints, the Okavango's streams hydrate vast blankets of greenspace. During the rainy season, wetlands and waterways laze over 5,800 square miles of Botswana flatland, creating habitat for a host of endangered species.