Borneo (Indonesian: Kalimantan) is the third-largest island in the world and the largest in Asia. It is located north of Java, west of Sulawesi and east of Sumatra. Borneo is home to one of the oldest rainforests in the world, and its mountain rainforests in the central highlands, elevated above 1000 meters, inhabit one of the richest biospheres. Its lowland rainforests cover most of the island, while it also has plenty of swamp forests, mangroves, grasslands, savannas and scrublands in the southern part of the island.
Borneo is also famous for its Dayak tribes. It is a loose term for over 200 riverine and hill-dwelling ethnic subgroups, located principally in the central and southern interior of Borneo, each with its own dialect, customs, laws, territory and culture. The Dayak are animist in belief; however, many converted to Islam and since the 19th century there has been mass conversion to Christianity. Many of them live in South Borneo and are called Malaris. They are also called hills Dayak hills or upstream Dayak, because their residences are located in the upper river and in the foothills of the Meratus mountains, which are also a border between South Kalimantan and East Kalimantan.