BOLIVIA // Nearly half of all mammal species in the Americas live in this 18,000-sq-km (6950-sq-mile) park, a marvel of biodiversity. The park soars from the sweltering tropical rainforest along the Tuichi River to the thin air of the Andes. It has become a model of ecotourism, with initiatives run by indigenous villagers. Ride an outboard canoe deep into the jungle in search of giant otters, jaguars and spectacled bears.