4Puerto Princesa Underground River, Palawan, Philippines
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This subterranean/ underground river is found in Palawan province in the Philippine Archipelago. It is considered one of the 7 New Wonders of Nature, aside from being a UNESCO world heritage site. The cave can be navigated by boat of up to 4km. But the deeper part of the cave is not possible for exploration due to lack of oxygen supply. Click the next ARROW to see the next image!
