The Philippines’ first UNESCO Global Geopark, Bohol Island, sits in the Visayas island group. The island’s geological identity has been pieced together over 150 million years, as periods of tectonic turbulence have raised the island from the ocean depths. Traces of the island’s subterranean past can be found in the limestone which forms characteristic karstic structures. The geopark abounds in karstic geosites such as caves, sinkholes and cone karst, including the famous cone-shaped Chocolate Hills in the centre of the geopark. The Danajon Double Barrier Reef along the northern coast is the only one of its kind in Southeast Asia and one of just six documented double barrier reefs on Earth; it provides visitors with a chance to discover 6 000 years of coral growth. Danajon Double Barrier Reef consists of two sets of large offshore coral reefs which were formed by a combination of favourable tidal currents and coral growth on a submarine ridge in the area.