Bordering the Sulu Sea to the northeast and the Java Sea to the South, it is separated by the Makassar Strait from the island of Sulawesi.
This island's Gunung Mulu National Park contains distinct karst formations and the largest underground chamber in the world. This area was used as a source of dragon's blood or mercury by Chinese merchants. It is home to Kinabalu National Park, which is located in its Crocker Range. Bordering the Sulu Sea to the northeast and the Java Sea to the South, it is separated by the Makassar Strait from the island of Sulawesi. This island is divided into seven ecoregions, and the burning of the peat swamp forests here has made Indonesia the third-largest CO2 emitter in the world. For 10 points, name this third-largest island in the world that contains Brunei and part of Malaysia.
This island's Gunung Mulu National Park contains distinct karst formations and the largest underground chamber in the world.
Borneo <RY>