At sunrise the cliffs turned to gold and, gloriously out of place in this usually parched wilderness, a cormorant dived for catfish in the pool.We began our return journey over a plateau of black limestone eroded into strange dimples that looked like egg trays for a dolls' house. As the overhanging precipices were beginning to glow dusky pink in the sunset, Lex and Loes unlocked a stone box and took out cooking equipment, sleeping bags and tents, which we each set up on the sand in the position we thought would give us the best morning view.We were not disappointed. We saw the tiny, twin hoof prints, no bigger than a pair of 5p coins, of the klipspringer and skirted its latrines - a klipspringer and his mate may use the same place to defecate over many years. Sometimes we startled kestrels, which rose from their look-out rocks and wheeled with motionless wings ever higher and higher on the desert thermals.By late afternoon we had reached a large, permanent pool in the river bed, flanked by a wide sandy beach, and a thicket of acacia trees. It had a striking effect, for the fields looked as if they were resting on the brink of the world and dimming the stars all night.The next day, we set off along the lip of the canyon, following tracks of Hartmann's mountain zebra and curly horned kudu. Everything is clean and simple, from the latrines to the solar heated bucket showers - simple, that is, for the guests: Lex and Loes have had to buy every item of building material, furniture and food from Keetmanshoop, some six hours' round trip away, or from Windhoek.The evening of our arrival, just after the sun had set leaving a streak of yellow and duck egg blue in the west, the full moon rose from the direction of South Africa's gold fields. Seven guest tents have been permanently pitched on stone bases along the very edge of the canyon with a view across miles and miles of fissures, gorges, hanging valleys and plateaux to a range of table mountains beyond.

First they must produce a recent doctor's certificate, as the only way to bring in medical aid is by helicopter from Windhoek, the capital, 700km away. And they must carry with them all their equipment, from tents to food and cooking utensils.Wanting more comfort, we opted for a newly opened alternative, the camp at the Canyon Nature Reserve, which has been set up by Lex Van Den Bosch, a Dutch biologist and tour guide, and his partner Loes Bolle. Now 100 miles long and up to 16 miles wide, this natural wonder is second only to the Grand Canyon as a gouge in the globe.Every year the Ministry of Environment and Tourism allows a limited number of hikers to spend five days walking 53 miles of the canyon's meanders - from the Main View Point opposite Hell's Corner to the hot springs at Ai Ais. Then some 500 million years ago, a fault opened up among them. Widened by glaciation and altered by more faults and wind erosion, canyons within canyons were formed until 50 million years ago a river began to flow down them.