Puerto Princesa, Palawan, Philippines
The Puerto Princesa Subterranean River National Park, located in Palawan, is one of the most impressive natural wonders in the Philippines. It features an 8.2-kilometer underground river that flows directly into the West Philippine Sea, making it one of the longest navigable underground rivers in the world.
Recognized as a UNESCO World Heritage Site and one of the New 7 Wonders of Nature, the park is home to stunning limestone karst formations, large cave chambers, and a rich ecosystem of bats, birds, and reptiles. Visitors explore the river through guided paddleboat tours.