The expedition, carried out in the months of February and March 2011 in the island of Palawan, saw the participation of as many as 30 Italian cavers, a Spaniard and a Belgian, in addition to the collaboration of the rangers of Puerto Princesa Subterranean River National Park and some local guides.
Thanks to recent explorations, the complex of the Subterranean River now reaches a development of about 34 km. A climb at the end of a branch in the initial part of the underground river, explored by Filipino cavers of the Gaia Exploring Club, has led to the discovery of the mysterious oriental collector, whose existence had been assumed on the basis of geological and structural considerations.
At the moment have been explored 4km of large galleries, and various side branches for at least another 500 m. The main gallery, dedicated to the anniversary of the birth of our country (150 Years Gallery), has long stretches of exceptional dimensions and areas with beautiful, eccentric concretions. In some places it was necessary to take off our shoes and walk barefoot, to avoid damaging the crystallization, while in others we had to put tape delimiters on to indicate the path and limit to the minimum the damage to the most concretioned areas. The tunnel ends in a vast hall, dedicated to the great explorer Ferdinand Magellan, who lost his life in the sea of Palawan in 1521.
In the Underground River has been redone the relief of the Australians influent, with the discovery of new lateral branches, for almost 2 km of total length.
Other surprises came from the nearby Little Underground River, waiting since 1989 a new visit. In this cave, which is "little" only if compared to his brother, were detected more than 3 km of tunnels and epi-phreatic pipes with sections of particular beauty.
In total were detected almost 10 km of cave, 7-8 km of the are new explorations.
On the external front, surveys were made in the highest areas of the southeastern sector of the massif of St. Paul, discovering several large sinkholes and some inlets. Unfortunately, some logistical difficulties have not allowed a more thorough investigation of this area, which remains one of the most promising of the ridge.
Other surveys were made in the northern sector. Here was descended a pit of 70 meters and opened the way for access to the vast plains full of depressions and sinkholes that characterize this area in front of the coast.
Finally, a few days before our return to Italy, we reached the summit of Mount Saint Paul, 1028 m high which, to our knowledge, had never been climbed before. Beyond the result itself, which rewards 22 years of research in this area, the climb to the summit allowed us to trace the path for future research in the high part of the massif, where a hanging valley hosts several seasonal sinkholes at 700 m above sea level, and open pits to almost 900 m above sea level