The Chocolate Hills are a geological formation in the Bohol province of the Philippines. There are at least 1,260 hills but there may be as many as 1,776 hills spread over an area of more than 50 square kilometres (20 sq miles). They are covered in green grass that turns brown during the dry season, hence the name.
The Chocolate Hills form a rolling terrain of haycock-shaped hills – mounds of a generally conical and almost symmetrical shape. These cone-shaped or dome-shaped hills are actually made of grass-covered limestone. During the dry season, the grass-covered hills dry up and turn chocolate brown.
The Chocolate Hills are conical karst hills similar to those seen in the limestone regions of Slovenia, Croatia, northern Puerto Rico, and Pinar del Río Province, Cuba. These hills consist of Late Pliocene to Early Pleistocene, thin to medium bedded, sandy to rubbly marine limestones. These limestones contain the abundant fossils of shallow marine foraminifera, coral, mollusks, and algae. These conical hills are geomorphological features called cockpit karst, which were created by a combination of the dissolution of limestone 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. These hills are separated by well developed flat plains and contain numerous caves and springs. The Chocolate Hills are considered to be a remarkable example of conical karst topography (Wikipedia).
The legend tells us a story worthy of a fantasy novel, but the truth is nothing particularly glamorous. Indeed, the ‘chocolate hills’ exist thanks to a rare geological formation which is impossible to explain. It is believed to be a cluster of coral and shell layers, dating back about two million years, which emerged on the surface through the process of plate tectonics.
But these hills are not the only interesting part of Bohol Island. It is also the place where the smallest primate in the world, the Tarsier, can be found. This little creature has bulging eyes and is halfway between a bat and a baby panda.