“Borneo is the third-largest island in the world and the largest in Asia. At the geographic centre of Maritime Southeast Asia, in relation to major Indonesian islands, it is located north of Java, west of Sulawesi, and east of Sumatra. The island is politically divided among three countries: Malaysia and Brunei in the north, and Indonesia to the south. It is the only island in the world to be politically administered by three countries at a time.”

“Before sea levels rose at the end of the last Ice Age, Borneo was part of the mainland of Asia, forming, with Java and Sumatra, the upland regions of a peninsula that extended east from present day Indochina. The South China Sea and Gulf of Thailand now submerge the former low-lying areas of the peninsula. Deeper waters separating Borneo from neighbouring Sulawesi prevented a land connection to that island, creating the divide known as Wallace's Line between Asian and Australia-New Guinea biological regions.”

“Borneo has significant cave systems. In Sarawak, the Clearwater Cave has one of the world's longest underground rivers while Deer Cave is home to over three million bats, with guano accumulated to over 100 metres. The Gomantong Caves in Sabah has been dubbed as the "Cockroach Cave" due to the presence of millions of cockroaches inside the cave. The Gunung Mulu National Park in Sarawak and Sangkulirang-Mangkalihat Karst in East Kalimantan which particularly a karst areas contains thousands of smaller caves.”