You can make your advanced reservations for your Underground River Tour here if you haven’t done so already. But before you come to the PPUR, here are 10 fun facts to know!

Interior shots of the PPUR courtesy of La Venta Geographical Exploration.

10. The Underground River was shaped by water for 30 million years.

The Underground River is located at the base of the karst limestone St. Paul mountain range. Through the ages, rainwater seeped into its cracks and crevices, creating water passages and tunnels. The tides coming from the sea also affects the ebb and flow of the water into the Underground River, slowly carving some walls of the cave.

9. The Underground River is located in a sprawling National Park.

The iconic landmark is found in the huge Puerto Princesa Subterranean River National Park. This park is so massive it’s about four-fifths the size of Honolulu, Hawaii. The National Park is a natural treasure in the Philippines because of its varied, dense, and old forests and numerous wildlife found nowhere else in the world.

8. Of the 13 forest types found in Asia, eight are found around the Underground River alone.

The National Park has a diverse range of forest formations–one of the most diverse in Asia! These include forest over ultramafic soils, forest over limestone soils, montane forest, freshwater swamp forest, lowland evergreen tropical rainforest, riverine forest, beach forest, and mangrove forest.

7. Two-thirds of all bird species in Palawan can be spotted in the National Park.

There are 252 known bird species in the Palawan archipelago. 165 of these are found in the National Park alone. That’s a staggering number! It’s two-thirds of all bird species in Palawan concentrated in this one virginal, Eden-like environment.

6. All the 15 endemic bird species of Palawan are found in the National Park.

There are 15 endemic bird species in Palawan. Endemic species are animals that are naturally found only in one specific area in the world. And of the 15, all of them are present in Puerto Princesa’s National Park! These include the Palawan Peacock Pheasant, the Yellow-Breasted Fruit Dove, and the Philippine Nightjar.

5. The long-tailed macaques around the Underground River love stealing food.

The area surrounding the mouth of the Underground River is home to long-tailed macaques. They are the only species of primates in the whole National Park. They’ve gotten used to being fed by tourists that now they love stealing food–chips in particular! So take care of your belongings! The sound of a plastic bag or a foil bag of chips drives them crazy.

4. The National Park is home to some of the oldest trees in Palawan.

The untouched landscape of the Puerto Princesa Subterranean River National Park is home to preserved forest trees and wildlife. Some of the oldest trees in Palawan is found in the park, going as old as 300 years! Here’s one for the books, a century-old Dao tree. It would take about 18 people interlinked by hand to circle the base of the tree.

3. The Underground River has crystals and minerals that can’t be found anywhere else in the world.

When the Italian scientific research team La Venta Geographical Exploration visited the Underground River in 2011, they were amazed. The scientists said only a few caves in the world have three to four minerals and yet the PPUR alone has 11! Incredible.

Three of these are new cave minerals that can’t be found anywhere else in the world. These are serrabrancaite, robertsite, and janggunite. Other notable minerals and crystals in the cave include calcite, gypsum, apatite, variscite, strengite, manganite, rhodochrosite, and pyrolusite.

2. You’ll find bone fossils of an age-old seacow embedded on the cave wall.

Also discovered by the Italian research team La Venta are bones so old they’ve turned into hardened rocks called fossils. Located in the deeper regions of the Underground River, the bones are part of the ribs of the ephemeral dugong or sea cow, which is still seen in Palawan’s waters today. According to the scientists, the bone fossils are about 20 million years old!

1. The Underground River would take you six hours if you were to boat until the end.

Actually, the number “8.2 kilometers” is the length of the explored passage of the Underground River. The entire length goes even farther. Who knows, maybe it leads to the belly of the earth! Of the entire explored length, however, only 4.3 kilometers is to open to public viewing as the latter half has limited oxygen. It would require a lot of technical know-how to get beyond that point.

And when you take a boat down the throat of this dark, death-quiet, and eerie passage, you’ll feel like it’s never going to end. What if your lamps run out of battery? What if the boat sinks? What if there’s a flood? What would you do in total darkness, surrounded by ancient saltwater and deep sea creatures?

Enjoy this thrilling tour today with Palawan’s oldest tour service provider. Booking is easy, secure, and hassle-free!