Philippines has 7,107 tropical islands, it is the second largest archipelago in the world and one of the great treasures of Southeast China.  Philippines is very reach in natural wonders, one of the best tourist destination in the country which has been officially declared as one of the 7 Wonders of the World is it's Puerto Princesa's Underground River in Palawan.  The park has a limestone karst mountain landscape. Main attraction here is St. Pauls Underground River Cave - more than 24 km long cave, which contains an 8.2 kilometers long underground section of Cabayugan River. A distinguishing feature of the river is that it winds through a cave before flowing directly into the West Philippine Sea and is navigable with a boat up to 4 kilometres deep from the sea.
More about Philippine tourism visit http://en.wikipedia.org/wiki/Tourism_in_the_Philippines

Top 10 Hidden Vacation Spots in the Philippines

If you don’t want to go to Boracay, Baguio, Puerto Galera or Subic, you might want to try Sagada, Mt. Banahaw, Siargao, Camiguin, Cagayan de Oro or Pagudpud. Or you might try these as-yet-unknown places for your vacation. Though these places may not be as luxurious as the usual tourist spots, low prices and warm local hospitality are added bonuses. In many of these places, residents are willing to accept visitors for home stays, just consult the local officials or ask around!