The Underground River is 10 million years old. On this journey you must wear a helmet. Inside there are hundred's of flying bats. You will see rock formations untouched and preserved for viewing only. A light is flashed from the Banca. There are 8 people allowed per Banca.
UPDATE SATURDAY MAY 10, 2008:
THE FOLLOWING INFORMATION ARRIVES FROM PINOY TODAY. RE UNDERGROUND RIVER. PUERTO PRINCESA CITY'S UNDERGROUND RIVER CLIMBS TO 24TH PLACE IN NEW 7 WONDERS SEARCH. LOCATED ON PALAWAN ISLAND, PHILIPPINES. LOCATED IN SITIO SABANG, BARANGAY CABAYUGAN IT'S UNDERGROUND 8.2 KILOMETER-LONG NAVIGABLE RIVER-CONSIDERED THE WORLD'S LONGEST. CURRENTLY IT IS DECLARED A WORLD HERITAGE SITE BY THE UNITED NATIONS ENVIRONMENT, SCIENTIFIC AND CULTURAL ORGANIZATION(UNESCO).