Belum Caves is the second largest cave in Indian subcontinent and the longest caves in plains of Indian Subcontinent, known for its stalactite and stalagmite formations. Belum Caves have long passages, spacious chambers, fresh water galleries and siphons. It is a natural underground cave formed by the constant flow of underground water. The caves reach its deepest point (150 feet from entrance level) at the point known as Pataalaganga. Belum Caves derive their name from "Bilum" Sanskrit word for caves. In Telugu language, it is called Belum Guhalu.