Tours of the limestone caves of Ugong Rock in Puerto Princesa which ends with a impressive views of the surrounding countryside and a 300-meter zip-line adventure. The rock is about 22 meters high and the tours are in fact a government-run environmental project started with the aim of preserving the rock while providing a source of income for the local community.
The name comes from the echoing sound made when you tap your knuckles against the hollow rock formations. Because the tour involves some tight spaces, there are body restrictions and children under 10 cannot join the tour.
