Puerto Princesa Subterranean River National Park, - The Puerto Princesa Subterranean River National Park features a spectacular limestone karst landscape with its underground river. A distinguishing feature of the river is that it flows directly into the sea, and the lower portion of the river is subject to tidal influences. The area also represents a significant habitat for biodiversity conservation. The site contains a full mountain to the sea ecosystem and protects forests, which are among the most significant in Asia.