This series of pretty limestone caves opens out right at the sea's edge on Walker Bay. An unusual feature of the caves is the lovely freshwater pools in which you can swim. They lie on the cave floor, only metres above sea level.

Cango Caves, near Oudtshoorn, South Africa

Even the thousands of tourists who traipse through it every year haven't spoiled the magic of this spectacular limestone cave system. The extensive stalagmites, stalactites and flow structures are still awesome and have an otherworldly quality when illuminated.

Wonder Cave, near Kromdraai, South Africa

This single cavern, reached by a lift, glitters with lights which reveal its limestone formations, cave pearls and the complete, calcified skeleton of an animal. It is part of the Kromdraai Conservancy, and there are regular tours.

Sterkfontein Caves, near Krugersdorp, South Africa

The site of the discovery of 'Mrs Ples' (Australopithecus africanus), this cave was home to some of the earliest-known homonids. Escorted walks and a small museum introduce visitors to some fascinating aspects of human evolution. A visit here is a pilgrimage to the dawn of humanity.

Sudwala Caves, near Nelspruit, South Africa

These dolomite caves, said to be about 2 000 million years old, contain some beautiful limestone formations, as well as fascinating fossilised algae. Tours of the outer caves are run daily and monthly 'crystal tours' are conducted into deeper chambers.

Arnhem Cave, Namibia

About 130km east of Windhoek is Namibia's longest cave system, stretching a length of 2 800m. It has few cave formations because water is scarce in the area, but it's the home of five species of bat. The cave is on a farm with camping facilities.

Chinhoyi Sleeping Pool, Zimbabwe

All that is left to see of this collapsed limestone cave is the large hole and a beautiful turquoise pool reflecting the sky. There are also some interesting tunnels through which you walk to reach the water's edge. The pool was once used as a place of execution for evil-doers who were hurled into the waters from the top.

Gcwihaba Caverns (Drotsky's Caves), Botswana

A low outcrop of rock in the dry and extremely remote northwestern Kalahari marks this huge system of dolomite caves. You'll need a 4x4 to get there, boots to wade through bat droppings, a torch or lamp with back-up batteries and provisions for two or three days. There are no facilities, and you must take great care not to get lost in the caves.

Grottes d'Anjohibe, Madagascar

This extensive cave system is hard to get to, and from November to May is completely inaccessible. Arrange for a guide to show you round the caverns and through the narrow passages. This is an overnight trip, so take along a tent and provisions.

Caverne Patate, Rodrigues, Mauritius

First obtain a permit at Port Mathurin to visit this dramatic cave. Then follow your guide through a hole in the middle of a field, and stay close to the light of his flambeau (a flame at the end of a pole) as you walk 600m through a wonderland of stalagmites, stalactites and other cave formations.