The "Chocolate Hills" are one of the things to see on Bohol Island. They have smooth rounded shapes, like scoops of ice cream, and their regularity makes one wonder if they were man-made. Their brown color is seasonal, due to dried grasses. Their formation is something of a geologic puzzle, but apparently the underlying rock is coral. There are many of them, scattered across much of Bohol Island, but tours usually bring visitors to see them from this viewpoint.