Cango Caves

The Cango Caves are located in Precambrian limestones at the foothills of the Swartberg range near the town of Oudtshoorn, in the Western Cape Province of South Africa. The principal cave is one of the country's finest, best known, and most popular tourist caves and attracts many visitors from overseas. Although the extensive system of tunnels and chambers go on for over 4 km, only about a quarter of this is open to visitors, who may proceed into the cave only in groups supervised by a guide.

Source: Wikipedia