Puerto Princesa's main source of pride is the Puerto Princesa Subterranean River a UNESCO World Heritage Site and one of the New 7 Wonders of Nature. The 8.2-kilometer waterway, said to be the longest traversable underground stream on the planet, winds its way underneath a mountain range, through the St. Paul Underground River Cave, and goes out into the South China Sea. The excursion through the whole framework alone is 24 kilometers in length. The whole region where the Underground River is found is really a national park and a model of biodiversity. More than 800 plant species, including very nearly 300 trees, call this zone home. Hoping to swim? Island jumping is one of the greatest draws of Puerto Princesa.