On the main island (also named Palawan) near Sabang, hike the three-mile (five-kilometer) Monkey Trail to Puerto Princesa Subterranean River National Park's navigable underground river. The five-mile (eight-kilometer) coastal rain forest route is home to long-tailed macaques, blue-naped parrots, and other indigenous wildlife. In the province’s northern Calamianes islands, Coron Island is considered one of the world’s top scuba diving destinations, offering World War II-vintage wreck diving and snorkeling in calm, crystalline waters. Nearby Culion Island, a former leper colony surrounded by sea grass beds and coral reefs, is an emerging ecotourism destination worth a day trip.