The Tadrart Acacus is a massif of sandstone towers, arches and canyons in the Fezzan of southwestern Libya, on the Algerian border near Ghat, carrying twelve thousand years of rock art in its shelters, from elephants and giraffes through cattle to camels as the Sahara dried, and it is crossed by four-wheel drive and camped in with Tuareg guides, when the country allows it. The paintings and engravings change subject as the visitor moves through the massif and through time: the oldest show the big game of a wet Sahara, hippos, elephants and giraffes hunted by round-headed figures, then the herds of the pastoral age, cattle with painted hides and their herders, then horses and chariots, and finally camels, the animal of the desert that the country had become; half the prehistoric pots tested from one shelter still held the chemical fingerprint of dairy fat, the earliest direct evidence of milking anywhere in Africa, and DNA read from two women naturally mummified in an Acacus shelter turned out to belong to a branch of humanity nobody knew existed. In 1958 an archaeologist found a mummified boy of about two and a half curled in a sack of antelope skin, the oldest known mummy in Africa.
The massif itself is the other half, towers of banded ochre and cream sandstone standing in sand, and the Afzejare arch springs straight out of the dune in one span with the sand running up to its foot, one of the great natural arches of the Sahara. The guides start the climbs before the heat, up soft dune crests above the rock islands, and the camps are plain, a fire, a mat and three rounds of sweet tea poured from a height until it foams, under a sky with no light for a hundred kilometres. The midwinter sun barely clears forty degrees, so the sandstone burns deep ochre all day and the low light throws the shadows that make the engravings readable. The Acacus is a gallery painted while the Sahara died, and the last pictures are of camels.