10 Famous Underground Caves in the World (with Map)
· 5. Majlis al Jinn Cave [SEE MAP] Majlis al Jinn is one of the largest underground caves in the world loed in a remote area of the Selma Plateau in Oman. Majlis al Jinn is a single cave chamber measuring about 310 meters by 225 meters (1,017 by 738 feet), with a domed ceiling 120 meters (393 feet) high.