The fourth-largest continent on earth, South America is a land of great extremes. The longest mountain range on the planet--the Andes--divides the continent from its northern coast on the sunny Caribbean to its southern tip at stormy Tierra del Fuego. Within its boundaries lies the world's highest active volcano (Chimborazo, in Ecuador), the world's highest waterfall (Angel Falls, in Venezuela), and the world's driest region (the Atacama Desert, of...