The Chocolate Hills are a geological formation in Bohol Province, Philippines. There are at least 1,260 hills (and maybe more) spread over an area of more than 50 square kilometres (20 sq mi). They are covered in green grass that turns brown (like chocolate) during the dry season, hence the name.
The Chocolate Hills are a famous tourist attraction of Bohol. They are on the provincial flag and seal as natural attractions of the province. They are in the Philippine Tourism Authority's list of tourist destinations in the Philippines. They have been declared the country's third National Geological Monument and proposed for inclusion in the UNESCO World Heritage List.
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. They probably started as corals growing in a warm, shallow sea about two million years ago. The hills consist of sandy to rubbly marine limestones. These limestones contain abundant fossils of foraminifera, coral, molluscs, and algae. These conical hills were created by limestone dissolving in rainfall and groundwater. There was erosion by rivers and streams after they were lifted above sea level. The hills are separated by flat plains and have numerous caves and springs. The Chocolate Hills are a remarkable example of conical karst topography.
