This cave system is believed to be one of the largest interconnected cave systems in the world by volume and the 8th longest cave in the world with a total length of 255.9 km. The system lies mainly under the western margins of Gunung Api between the Melinau Gorge and Cave of the Winds.

The first exploration by speleologists was during the 1977/78 Royal Geographical Society Mulu Sarawak Expedition which discovered the first 24km of Clearwater Cave. Then from 1978 to 1984, many expeditions were organized, increasing the length of the cave to 51km. In 1988 a small expedition connected Cave of the Winds to Clearwater and discovered the 24km long Blackrock Cave, which was later also connected to the Clearwater cave system in 1991. A further 15km of passage was also added to Clearwater Cave itself in that same year. In addition, Drunken Forest and Leopard Cave were also connected to the Clearwater cave system in 1990 and 1993.

In 2003, after 10 years, a major turning point occurred when Whiterock Cave was discovered north of Blackrock Cave. Through many expeditions that took place between 2005 and 2018, explorers found the total length of Whiterock Cave to be 101km, making it the largest part of the Clearwater system.

Most recently, in 2022, the Racer Cave and Easter Cave are connected to the cave system, bringing the total length to 255.9km.

According to Wikipedia, mulucaves.org