Rising from the heart of Africa astride the equator, Uganda's volcanic mountains are one of the last refuges of the endangered mountain gorilla. The rain forests that shroud their slopes also shelter chimpanzees and monkeys, making Uganda the world’s best destination for primate viewing. Only 900 or so wild mountain gorillas remain, and tracking them through the dense forests of Bwindi Impenetrable National Park is one of the top safari experiences anywhere in Africa. In guided groups of no more than eight travelers, search for one of the habituated gorilla groups that are accustomed to human encounters. Each visit with the gorillas lasts one hour. To come face to face with these powerful yet peaceable wild creatures, so evidently intelligent, is spine-tingling.