The Cango Caves are 29 km from Oudtshoorn, at the head of the picturesque Cango Valley. 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 four kilometers, only about a quarter of this is open to visitors, who may proceed into the cave only in groups supervised by a guide. Tours are conducted at regular intervals on most days - there is a "Standard Tour" which takes an hour and an "Adventure Tour" which takes an hour and a half. The "Adventure Tour" consists of crawling through narrow passages and climbing up steep rock formations guided by small lights. The caves contain spectacular halls and grand limestone formations (on both tours) as well as some rather small passages on the Adventure Tour.