Puerto Princesa Underground River

Palawan, Luzon

The Puerto Princesa Subterranean River National Park is located about 50 kilometres (30 mi) north of the city centre of Puerto Princesa, Palawan, Philippines. The river is also called Puerto Princesa Underground River. The national park is located in the Saint Paul Mountain Range on the northern coast of the island. It is bordered by St. Paul Bay to the north and the Babuyan River to the east. The City Government of Puerto Princesa has managed the National Park since 1992. It is also known as St. Paul's Subterranean River National Park, or St. Paul Underground River. The entrance to the Subterranean River is a short hike from the town of Sabang.

Birds comprise the largest group of vertebrates found in the park. Of the 252 bird species known to occur in Palawan, a total of 165 species of birds were recorded in the park. This represents 67% of the total birds and all of the 15 endemic bird species of Palawan.
Puerto Princesa Underground River was entered as the Philippine entry - and topped the first round of voting - in the New7Wonders of Nature competition, and on July 28, 2011, after the second round of voting, it was declared 1 of 28 finalists. On November 11, 2011 it was provisionally chosen as one of the "New7Wonders of Nature", together with the Amazonia, Halong Bay, Iguazu Falls, Jeju Island, Komodo Island, and Table Mountain.
The park has a limestone karst mountain landscape with an 8.2 kilometer navigable underground river. A distinguishing feature of the river is that it winds through a cave before flowing directly into the West Philippine Sea. It includes major formations of stalactites and stalagmites, and several large chambers. The lower portion of the river is subject to tidal influences. Until the 2007 discovery of an underground river in Mexico's Yucatan Peninsula, the Puerto Princesa Subterranean River was reputed to be the world's longest underground river.
The area also represents a habitat for biodiversity conservation. The site contains a full mountain-to-the-sea ecosystem and has some of the most important forests in Asia. It was inscribed by UNESCO as a World Heritage Site on December 4, 1999.