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. In the mists of geological time, a sea bed was lifted miles above the level of the ocean and weathered into ranges of table mountains. At ground level - amongst sand and quartzite boulders - grew fat succulents, southern Africa's answer to the cactus.Some 110 miles from the town of Keetmanshoop, invisible until you are almost on top of it, the Fish River Canyon is a huge tear in the face of the earth.

At regular intervals, interspersed with the huge nests of sociable weaver birds, we passed pale chanting goshawks on the telegraph poles, watching for prey. But we were delighted by the unseasonal storm for, though the Fish River itself was no longer running when we arrived, water was still cascading down the creeks and seeping through the Canyon floor to replenish the permanent pools. We drove down to base camp across mile after mile of high desert and scrub savannah. Worried and apologetic because of the state of the rough lane, the manager of the Canyon Nature Park rang to warn us that the camp could only be reached in a 4x4. Over two-and-a-half days, 74mm of rain fell in the Fish River Canyon - a whole year's rainfall. The gravel road was covered with treacherous drifts of sand deposited by ephemeral rivers; part of the lane leading to the canyon itself was washed away and the airstrip was filled with fissures created by swift flowing floods. Charter flights direct to Luxor operate through companies such as Tradewinds (01706 260000) or Thomson (0990 502399) Expect to pay around pounds 250 for a flight..