These caves are estimated to be over 20 million years old. Located in a limestone belt, the caves were carved by rainwater seeping into fissures in the limestone, dissolving it and forming an extensive network of caverns and tunnels. Stalactites, stalagmites and flowstones have formed from the crystalline solution, providing some of the most staggering formations, such as Cleopatra’s Needle, a nine-meter high stalagmite in excess of 150,000 years old and still growing.
The temperature in the caves remains a constant 18°C (67°F) and the atmosphere is humid.
Not much lives in the caves beyond a small colony of bats. Skeletons of three genets (small cats) have been found deep within suggesting that there may be, or have been, another entrance at some stage.
Only around one quarter of the four km of caves are open to visitors and only in groups with a guide. Tours are at regular intervals daily and last an hour (the standard tour) or an hour and a half (the adventure tour). This latter tour involves scrambling through narrow passageways and climbing up steep rock formations.
The nearest town is Oudtshoorn, which is around 29 km (18 mi) away.
Tours must be booked in advance due to popularity with visitors and are not suitable for asthmatics or those suffering from back trouble or claustrophobia.
The caves were supposedly first discovered in 1780 by a local farmer, Jacobus Van Zyl, after whom one of the main chambers is named.