Gua Nasib Bagus (Good Luck Cave) or Lubang Nasib Bagus is a cave located in the state of Sarawak in Malaysia. It is one of many caves found within Gunung Mulu National Park, a World Heritage Site on the island of Borneo.
The cave houses the largest known underground chamber in the world, Sarawak Chamber. It is 2,300 feet (about 700 m) long, 1,300 feet (about 396 m) wide, and around 230 feet (about 70 m) high.[1]