The Puerto Princesa Subterranean River National Park, also known as St. Paul Underground River, is located about 50 km north of the city of Puerto Princesa, Palawan and features a limestone karst mountain landscape with an 8.2 km. navigable underground river. A distinguishing feature of the river is that it winds through a cave before flowing directly into the South China Sea.
Inside the cave, major formations of stalactites, stalagmites and several large chambers abound with the lower portion of the river subject to tidal influences. The underground river is reputed to be the world's longest and at the mouth of the cave, a clear lagoon is framed by ancient trees growing right to the water's edge. Monkeys, large monitor lizards, and squirrels find their niche on the beach near the cave.
The Puerto Princesa Subterranean River National Park in Palawan Philippines is one of the New 7 Wonders of Nature, together with HaLong Bay in Vietnam, The Amazon in South America, Jeju Island in South Korea, Iguazu Falls in Argentina/Brazil, Table Mountain in South Africa and Komodo in Indonesia.