My sister and her husband explored the Underground River during their holiday in Palawan, Philippines last year.
They took a boat tour to the place with a bunch of other tourists.
What a beautiful place! I can't wait to see it in person one sweet day. Hubby promised to take me and the kids there, just don't know yet when it will happen. :)
I did some research and here's what i found:
The Underground River is located only 50 kilometers north of the island capital Puerto Princesa which has an airport with daily flight from Manila & Cebu International Airports.
For years the Underground River was accessible to only dedicated adventures who were prepared to travel for hours in four-wheel drives along dirt and then stay in primitive accommodation.
The great news is new roads have been made enabling visitors to travel in comfort and safety to Sabang in half the time, but it just got even better with the opening this year of the new Sheridan Beach Resort right in the heart of Sabang.
Additional Info: The New 7 Wonders of Nature are now being democratically voted for by people all around the world and its down to 28 Official Finalist Candidates (from an original 77) with the Palawan Underground River included. ~SOURCE