Puerto Princesa Underground River National Park, Palawan The Puerto Princesa Underground River belong to the most impressive caves systems in the world and one of the New Seven Wonders of Nature. It is the Second Longest Underground River in the World and the Longest Underground River in Asia with 8.2 km long traversable underground river that directly flows to the sea. The river is flowing openly under the St Paul Mountain Range which is situated on the mid-western coast of Read More …