East Malaysia, on the island of Borneo, has a coastline of . It is divided between coastal regions, hills and valleys, and a mountainous interior. The Crocker Range extends northwards from Sarawak, dividing the state of Sabah. It is the location of the high Mount Kinabalu, the tallest mountain in Malaysia. Mount Kinabalu is located in the Kinabalu National Park, which is protected as one of the four UNESCO World Heritage Sites in Malaysia. The highest mountain ranges form the border between Malaysia and Indonesia. Sarawak contains the Mulu Caves, the largest cave system in the world, in the Gunung Mulu National Park which is also a World Heritage Site.