Puerto Princesa Underground River
The Cabayugan River runs 8.2 km under a limestone mountain before it reaches the sea, and paddle boats take visitors about 1.5 km of that. UNESCO inscribed it in 1999 and it was voted a New7Wonder of Nature in 2012. Entry is capped at 900 people a day and permits come from the booking office in the city, so arrange it before you fly.
