Mahmud, my travel companion tells me he's camped in the dunes.
"Never again," he shudders.
I ask him if it was dangerous because of the proximity with the unstable border zones.
"No," he says, emphatically "I hate sand."
Coming from a Libyan whose country is about 95 per cent desert (although not all of this is sand) I find this amusing.
"There's never enough water to wash properly for prayers," Mahmud explains.
A strict Muslim, he prays five times a day and although the full ablution ritual is not expected if water is not available, Mahmud doesn't like compromising.
We track along the length of the dunes, stopping briefly at one of the most dire police postings in the world. Because Wadi Methkandoush is on what passes for Libya's tourist trail, tourist police are sent to man a check-point to check permits and to ensure travellers make it in and out of the area in safety. Their camp is a collection of forlorn concrete sentry station, a corrugated iron longdrop and a tumbledown shack.
"This is where they send the bad policemen," Mahmud explains, as the driver hands over some cigarettes to the two scruffy downtrodden individuals who emerge from the hut.
"If they are lazy or don't behave properly they are sent here as punishment for many months at a time." I'm looking at a police officers' gulag. Mahmud tells me that unsurprisingly just one trip here usually does the trick in reforming the wayward.
Beyond the check post the landscape changes as we drive on to the Ocean of Stones. Deep red basalt boulders, their upper surfaces polished black by windblown sand stretches into the distance as far as the eye can see.
It's an apocalyptic landscape with the additional attraction of being a favourite habitat for snakes. It's probably too cold for them to be basking on the rocks at present but even so there's no way I'm getting out of the vehicle here.
After an hour of being thrown around the cab, the evil eye pendant hanging from the rear view mirror swinging crazily all the while, we stop on the edge of the wadi (valley).
Although there's no permanent surface water source down there, the wadi is a sinuous ribbon of green - there are gnarled trees and dense thickets of grasses and small shrubs.
On the opposite side of the valley is a cliff face of vertical rock slabs, slashed with fractures and with piles of boulders and scree at their feet.
Leaving the 4WDS at the top we make our way across to the cliff. At first I can see nothing at all but Mahmud points up to the top and I can make out the dark outlines of a giraffe stalking across a slab of rock. The giraffe is beautifully patterned, as are his companions nearby which seem to be galloping across a long vanished savannah. They are full of life and movement, carved into the rock at least 12,000 years ago.
We walk along the cliff face and more animals appear - hippopotamus, elephant, ostrich and rhinoceros. When the carvers were at work here, the Sahara was in a temperate age and wild animals abounded, attracting human hunters and inspiring the community's artists to record what they saw in profusion around them. Humans later brought with them domesticated animals which are also recorded in some of the younger carvings in the area.
Although most of the carvings are situated high on the cliffs, a two-metre-long crocodile has been incised into a rock near the valley floor - it stalks along a rock face, vibrant and fresh.
Wadi Methkandoush's piece de resistance however, is situated high on a bluff. Here two big cats with pointed ears stand on their back legs, sparring at each other with their front paws. For 12,000 years they have been frozen in time, testament to an artistic flowering in an age of plenty in the Sahara that now stand marooned in the Ocean of Stones.
