Chocolate Hills, Philippines

The Chocolate Hills are an unusual geological formation in Bohol Province, Philippines. They form a rolling terrain of haycock hills – mounds of a generally conical and almost symmetrical shape. The hills vary in sizes from 30 to 50 meters (98 to 160 ft) high with the largest being 120 meters (390 ft) in height. There are approximately 1,776 hills spread over an area of more than 50 km2 (20 sq mi) including throughout the towns of Carmen, Batuan, and Sagbayan. They are covered in grasses, composites and ferns that turn chocolate-brown color during the dry season, hence the name. 

The Philippine hills consist of Late Pliocene to Early Pleistocene, thin to medium bedded, sandy to rubbly marine limestones. These limestones contain abundant fossils of shallow marine foraminifera, coral, mollusks, and algae. The conical karst hills, called mogote, were created by a combination of the dissolution of limestones by rainfall, surface water, and groundwater and their subaerial erosion by rivers and streams after they had been uplifted above sea level and fractured by tectonic processes. The hills are separated by well developed flat plains (which are cultivated with rice and other cash crops) and contain numerous caves and springs.