Ujung Kulon National Park, Indonesia

Located in the Western tip of Java, Indonesia, Ujung Kulon National Park is the last refuge of the Java rhinoceros, the most endangered animal in the world. The park is also next to Anak Krakatoa, one of the most active volcanoes in the world. But keeping a national park pristine on the world's most-populated island has been an uphill battle for Indonesia. Poachers already drove the Javan tiger to extinction in the '70s and have narrowed the rhino population to less than 40 individuals.