In November 2007 I joined a recce organised by London-based Simoon Travel and Tanezrouft Voyages. Over 11 days we walked about 200kms from south of Arak through the northeastern Immidir to the Amguid Crater and the Bou Zerafa dunes beyond.
The Immidir, aka the ‘Monts du Mouydir‘ on the Mich map, left, is a region of plateaux, escarpments and canyons that spread north and east of the Arak Gorge on the Trans-Sahara Highway. To the south are the lovely exfoliated granite domes around Tidikmar and Moulay Hassan which we visited in 2005, and to the north and west of the TSH are a number of low plateaux, sand sheets and small ergs of the Adrar Ahnet.
A few groups have followed part of our route through the Immidir before, and I know of a few others who’ve approached the crater from the Habedra piste by car and walked the last 10-20 kms, but no one has combined both. It was an idea I’d offered a couple of years ago with Tanezrouft and then proposed to Libya specialists Simoon. They liked it, found some people and so here we were.
After arriving at In Salah, we drove south 300kms along the Trans Sahara Highway to this valley a few kms beyond Arak settlement. The camels and crew had been waiting a couple of days. Next morning we set off north up the Ighaghar valley in the middle left of the picture.
The first few days with a south wind were hot and at times the terrain proved to be tougher for the camels than I expected. On Day 1 a few camels stumbled and lost their loads getting to the top of the Taflout Pass pictured above.
By the next day we had a morning wandering through the cool box canyons and welcome gueltas or aguelmam for which the Immidir is best known. This place is just behind the Arak Gorge.
Although there was rock art to be found, what we saw wasn’t really up to the quality and density of the eastern N’Ajjer, Akakus or the Gilf.
Most days we came across a desert mosque or some sort, although I’ve never seen the ‘pewed’ examples we found in the Immidir. The inset shows a similar structure viewed from Google Earth at Aguelman Rahla guelta, 13kms directly north of the crater at the mouth of Oued Tafrakrek (see Google image below). Google Earth shows the permanent guelta surrounded by pre-islamic tombs (including the less common keyhole type) which suggests like many Sahara oueds, the place has long been inhabited.
What tracks there were were old camel pistes across the hammada. Rubble like this was tough on boots and feet; most of us got blisters. Even the camels needed treating for cuts and one night the guides made them some hide socks. Some days the caravan took alternative, easier routes. Daily distances varied between 14 and 24kms. By the end we didn’t even notice a 14-km morning. The route is inaccessible to vehicles but we passed plenty of mouflon, jackal, gazelle and fennec trails and once saw camel tracks other than our own.
This was a nice day; about 24 clicks round the back of the guelta below, over a ridge where one camel collapsed and needed unpacking and a gentle kicking. Then round to the big oued above which fed the gorge pictured below and into a series of small valleys where I found an intact pot.
Later it was fun marching on alone trying to catch up the caravan somewhere up ahead with the security of knowing the others were following. At times it took a little tracking to uncover the lead camels’ trail. Easy in sand, trickier on rock.
One lunch stop was by a deeply-carved gorge strung out with several waterholes (gueltas) and this arch.
With no wells along the walking stage, the crew refilled from sources like this. People are put off by the colour but of course what makes you ill you can’t see, even in crystal clear water. Being early in the cool season following the summer rains, the water was probably fresh enough and if the crew could drink it so ought I. So as an experiment I drank the water as it came but didn’t get ill.
Interestingly ‘flying’ over our route on Google Earth reveals the region awash with gueltas. The gorge above (N24.317′ E 03° 58.506′) is almost one long pool and elsewhere we or the camels would not have got through some valleys and gorges without swimming.
Mohamed H of Agence Tanezrouft and Sidi Ali our cook coming through. Sidi and the crew’s work started when we stopped walking for the day and carried on until we set off before them next morning so we didn’t resent them riding. We could too and those that did remarked what a relief it was to be able to look around at the scenery instead of dodging the next rock underfoot.
After a while it didn’t take much hesitation for us to grab a quick wash or launder at any guelta we came across, or even dive in for a swim. Like all tassilis, the Immidir has countless gueltas which make it suited to camel trekking. You can see from the ‘tide lines’ how deep this one fills after heavy rains.
Some shade always cropped up around lunchtime or ‘midi’. Usually we’d have to wait for Sidi Ali and his lunch camels to catch up. Then while we siesta’d the main caravan might pass through and keep going, usually getting to our evening camp ahead of us.
Food. Breakfast was light: coffee with hot milk and baguettes, sand bread or pancakes with jam and marg. We were sometimes given dates and a soft drink for the road. Lunch was a heap of mixed salad or veggie rice followed by mint tea and an orange while they lasted. We has more tea/coffee and biscuits soon after we stopped walking for the day. Dinner was soup and bread, a main course of cous cous/rice/pasta and stew – all variations on dried goat meat followed by an orange and mint tea. Most of us brought some sort of snacks and I brought my v-kettle (right) with drinks/soups which came in handy while waiting for the lunch camel to turn up.
Although I ate much less then I normally do, I eat too much anyway and saw the trek as a chance for a bit of a detox. I lost about half a stone but was never hungry. The daily ritual of walking, sleeping, chatting, eating and resting was very satisfying; as always the desert demonstrates how little you need to be content.
I carried about 2.5 litres of water in a Camelbak (bigger than most) and never ran out. On the earlier hotter days at about 30°C I got through 2L a day, later in the low 20s it was about a litre. About the same as summer in England.
Come the big day the chattering subsided but we were still smiling when we got to the top of this gnaaarly climb, having unnecessarily gone up and down another ridge (see map below). With us we carried overnight gear, a bit of food and -no surprise to me having done these sort of walks before – not enough water. At the top of the climb we got our first sight of the Bou Zerafa dunefield 20 kms to the north and from this picture overlooking the camel route below the crater was only about 6km to the east.
Before we set off from Arak I didn’t have a clue which way our guide Yahia was going to reach Bou Zerafa other than north some way. A map didn’t mean much to him so there was little point asking or pointing and Tamachek names don’t always match the map’s Arabic. I presume then it was a total fluke when his route led far to the east below the Adrar Tassedit escarpment before turning north up the Oued Bou Zerafa – or Oued Tassedit as they called it. It could not have passed closer to the crater site.
So east we went. The broken terrain reminded me of a mild version of Ginge Fullen’s attempt to climb Bittu Bitti, Libya’s highest peak (see p.377 in the book). Between us and the horizon where the crater surely lay were any number of chasms, clefts and gorges. Near this point we passed the 150-km mark which put the crater at nearly 100 miles from our departure point near Arak.
Just on sunset and having covered 7 tough kms in 3.5 hours, we sat ourselves down in the middle of the crater pan. Not sure what we’re all laughing about; we each have less than a litre of water left so tomorrow was going to be a bit of a march but our goal had been accomplished.
From the left: me, Yahia the guide, Francoise, Jon the photographer, Imogen, Amelia of Simoon, Bob, Amelia’s husband Lex who tracked the whole route on GPS and Tom.
The crater is thought to have been formed less than 100,000 years ago and the first recorded visit was by a French geologist in 1969. For us it would have been nice to explore it in sunlight and I’d also hoped to take a hike over to the Oued Tafrakrek rim a couple of clicks to the east. But having chatted with Mohamed on the sat phone, Yahia explained to us the camels were already heading for the dunes so to intercept them we had a longer cross-country walk the next day. I went to sleep thirsty, woke up thirsty and at first light decided to drink my last cupful while others chose to save a few drops for the hike. To make the most of the cool morning we climbed out of the unlit crater at first light and set off northwest to the dunes.
Here’s part of our route in red over the Adrar Tassedit plateau 8 days after leaving Arak. After lunch (009 LCH if you have bionic eyes) and repacking our gear we left the caravan trail in green, crossed a needless ridge (below the ‘A’ and then climbed back onto the plateau (‘009 DN VW’; the group shot 4 pics above) and then went up and down past ‘009 150KM’ to the crater at ‘706’. The map above is about 15 miles/25kms wide.
Although we were unsure to put our trust in Yahia as he’d never been here either, next day he led us to the dunes where our camels were waiting. Knowing water was scarce he lured us on, keeping just out of reach so there was no discussion about which way to go. As the return route and waypoints show, his Tuareg ‘GPS’ was spot on. Apart from the easily-remedied water issues our route to the crater was as good as could be expected.
In 2009 we started at dawn at ‘557’ a bit to the north of our lunch spot, above the meander of the ‘T’ on the map. We climbed up the valley side with a bit of scrambling and had a much easier 2.5hr/6km each way walk to the crater. Next day we followed the green route along the canyon to the dunes and beyond, probably 30km but no one noticed by now.
With some (myself included) a bit more parched than others (notably the women), we finally staggered off the plateau and onto the sands some 6 hours and 16 kms from the crater – much further than we imagined and having drunk no- or just a couple of sips of water. Everyone had quietly focused on the task. Luckily it was another cool day and of course we knew the crew was out there somewhere with water.
Once on the sands some desperados cracked and drained the last gritty dregs from their hydrators while Yahia dashed off to track down the caravan out in the sands. A few minutes later Mohamed came galloping in with some water.
We spent the rest of the day idling about and drinking everything they brought us. That evening, while contemplating the transit of Orion and Copernicus’ theory that meteorites never strike in the same place twice, a shooting star tore in low over the Tassedit plateau above the crater. With a bright green trail breaking up behind it, somewhere out there a new sprinkling of space debris had scattered itself across the desert floor. As we discussed the startling phenomenon a sonic ‘b-boom’ rippled over the sands, suggesting a meteorite had indeed breached the atmosphere. Someone knew the speed of sound and estimating the time after the sighting, Tom worked out it had fallen about 50 miles away, well beyond the crater. With this suitably astral climax to our crater day, Copernicus was proved right – again.
Next day we headed into the dunes for some exercise. Some took the high road…
… some took the low. We passed Bou Zerafa well marked on the maps. It was sanded over but Yahia assured us there was water a metre below. Winding up our 10-day rocky plateau trek in the glowing orange sands of an erg was perfect – another highlight after the crater.
Next morning the cars turned up from In Salah with fresh food and water. At this point my camera passed out but we carried on northeast alongside a dune ridge to one more camp (passing some lovely pestle-like moules to go with the countless grinders lying around). Another short morning followed to knock off ‘200kms’ according to Lex’s GPS tracking, right by an unmarked well with good water.
We drove from there northwest to Tin Habedra well (sanded in) and then directly west along the Habedra piste passing escarpments lined with tall cairns and small, palmy sources while chased by a storm front. It showered a bit that evening and most took to the tents for the first time as lightning flashes circled us along the horizon. Then at 2am a bolt exploded nearby and a heavy shower drenched the camp. The tents held off the worst of it but next morning by the time we’d got the fire lit most weren’t in the mood for the planned splash about at Tiguelmine guelta on the old Hoggar route. We headed directly back for In Salah, a great feast at Mohamed’s, a plane to Algiers and home.
I was back in Tamanrasset, this time with a small group of camel trekkers. Year by year it gets more difficult to travel out here and a few weeks earlier Algeria cancelled all tourist visas to the desert– most probably due to weapons slipping out of Libya west towards Mali where some kind of rebellion has already broken out. As a result three missed out and only 7 got visas: 3 Americans: Diane and Steve from Tuscon and Patrick (later just ‘Rick’) from NYC, plus Rob from Bermuda, Hannah from Alderney, Rob from Bristol and Mike from Staffs who’d been on a 2006 Gilf trip I’d led for a tour agency. Right: Camel trekking ebook.
It’s nice to drive cars and ride bikes in the desert, but these days that can feel rather conspicuous as you come down from the north. With camels you slip into Tam on the midnight plane from Algiers, and 24 hours later are out in the sticks, largely unnoticed. Any anxieties I had about the ‘Grand Sud’ being closed and us getting stuck- or sent back from Tam came to nothing. And I knew once we were out bush all would be fine.
I’d originally planned a meaty 4-week trek from Tam to Djanet, but decided mid-ye that left us exposed along the Niger border where an Italian woman had been grabbed a year ago. She’s now one of 12 Europeans (as well as local police and others) in the hands of AQIM in north Mali. I’ve just started reading this book about the history behind these events and if nothing else, it underlines how dire it would to be dragged around the oueds of northern Mali for months at a time, suffering injuries and other ailments, with no shelter, terrible food and dirty water.
So, with Tam-Djanet a bit sketchy, the plan boiled down to repeating the reliable Amguid Crater trek I’d done a couple of times over the years for Simoon, then drive back down to the Hoggar and spend a week walking up to Assekrem and back (report on that later). I was using a new agency this time, Ben Kada, an established operator recommended by a friend of a friend and so, along with all the other unknowns, I was hoping they were going to deliver – which in the end they did better than I’d expected. Last November a fake guide who’d infiltrated a well-known agency in Tam to set up a kidnap had been sent down, so it’s hard not to be a little paranoid these days, even if the Algerian security services are on it.
Next evening ee arrived at the same camp south of Arak (left) which we’d used on the recce tour in 2007 with Simoon. The first day kicked off a stiff climb around midday which had been tough on the fully loaded camels, but this time our caravan managed fine. New Year’s Day followed, a spectacular amble through the box canyons of Tissadout, with lunch under a lone tree, a guelta swim and a rock art cave all ending at a great camp spot in the Adjror valley (home of Beetle guelta; these names established on the 2007 recce). Here we met the only other tourists in Algeria who were taking a two-weeker out of Arak. There followed a long haul to Igharghar valley, past the Haribo Tree, the Lunch Cave and the desert mosque, before diverting to a deep slot canyon and tombs which I’d missed on previous visits. Interestingly the deep cleft (left) is actually the river which breaks out through the gap in the ranges at Tadjemout, where we’ve started the tour on previous occasions. Once at camp I got rather lost in the dark while looking for firewood, returning to the camp from the opposite direction, but no one seemed to notice.
Next day I asked to Mohamed, our genial 72-year old guide, to visit the impressive three-tiered gueltas (rain-fed waterhole) we’d lunched at in 2007, but which had been skipped by subsequent guides. On the way there ‘Rick’ lost us while engrossed in the manual of his new Nikon Tankbuster, but did the right thing by getting onto high ground and was back on our trail by the time Moh had backtracked to find him. The same had happened to me hereabouts a tour or two ago when I’d stopped off and ended up chasing half-burned toilet paper in the breeze. Now Rick also knew that chilling feeling when you lose sight of the group, any trace of their tracks, and haven’t got a clue which way is up.
As it happens the many tiered gueltas of Tin Karabatine were very low on water – as were many other rock pools in the region this year – but we managed to launder and wash anyway, while Moh instructed us to follow the canyon’s right rim upstream for 30 minutes to meet him and Tayeb the cook with the lunch camel later, in the valley above. It seemed a bit of a leap of faith, but we passed the test and met up close to the ever-serendipitous acacia which crops up at these times. Later on Tayeb was similarly tested by Mohamed, with less success.
I knew well that the afternoon ahead was one of the nicest stages of the walk, made all the better by spotting a galloping mouflon (barbary sheep) as big as a donkey, as well as cheetah tracks (right), before we wound our way through the sandy outcrops down to woodless Camp IV. Next day was another long walk, 25km over to Tahaft; down into the big valley with a lazy lunch under a thorn-free tamarisk while the crew filled up from the soak. As on previous walks, we staggered in as the sun was setting behind us but very soon Tayeb had the tea and biscuits laid out while we waited for dinner. Up till that day, as with all that followed, there was very little wind until maybe the late afternoon which kept things warm, though it dropped to near-freezing most nights, and sometimes below.
Even with a waypoint, I blundered around next morning to locate our discrete 100KM marker from 2007, until Diane spotted it and we lined up for the now traditional photo (left). Mohamed diverted soon after to chat up a couple of bedraggled goat nomads about pasture and water up ahead. He’d been here once in the last 25 years if I understood him correctly, but knew all the spots and was still showing me new places and routes, even on my fourth visit here. After a splash in the Tahaft slot-guelta and another lazy lunch, Moh led us on a great cross-country scramble down to the ‘lost oasis’ of Tin Djerane
where birds twittered and jackal tracks set hard in the mud. We heard their yelps on a few nights, but I’ve never actually seen one out in the desert. Along the camel trails you’ll regularly find stone slabs laid up into conical ‘goat holders’ to protect them from the overnight jackals.
More sparkling gueltas and even flower-clad lawns led to Camel Branding Camp V along the south edge of the Tissadert escarpment. This place is surrounded by ancient tombs, many of which have been annotated on Google Earth by ‘Ken Grok’. There’s a ‘keyhole tomb’ a couple of minutes from camp (above left), another 700 metres away which we passed close by later, but the strikingly huge antenna tomb (right, on GE) I led us to with the GPS was so big it was hard to visualise at ground level.
Following another swim at a big guelta, we failed to meet up with Tayeb and the lunch camel. Tayeb was from Tazrouk down in the Hoggar and this was his first visit to the Immidir which Mohamed and his aged crew, Halil and Ahmed, knew well. So it was a bit of a reach asking him to meet us up ahead in a creek he’d never seen. We zig-zagged around while Moh tried to pick up the trail and at one point I strolled right across another huge keyhole tomb. Eventually Mohamed found fresh tracks and around 3pm we spotted Tayeb sat patiently alongside an acacia-lined oued. Ravenous by now, he got an unfair bollocking while we tucked into the heaped platters of salad which Tayeb prepared for us daily.
Moh had suggested that to get to the crater we take the next oued east after Tissadert, the Oued Taferekrak (according to the IGN map, below). Approaching the crater from this side was something I’d wanted to try for a while as the site lies just 500 metres from the canyon rim and ends up at the interesting Aguelman Rahla, surrounded by more pre-islamic tombs as well as dunes.
This also happened to be along the approach route to the crater we’d planned on Desert Riders back in 2003, going as far as leaving a fuel and water cache at Foum el Mahek gap to the east a year earlier (see map, right). That trip did not end so well, but having now walked up it, I’m not so sure riding the lardy Honda XRLs would have been at all easy up here.
After a light overnight freeze, we set off up the wide canyon (left) and as expected, met some goat nomads who agreed to sell us an animal for a hefty €75. It had been the same price last year, but down in the Hoggar I was later quoted €50. Still, for a tenner each we ate well for three days and the crew got an unexpected treat too.
So, while the old men and Tayeb prepared to chop up the goat, we set off for the crater up the steep canyonside (right) with Salah, Mohamed’s 18-year-old son. After just an hour of huffing and puffing we looked down onto the crater (below), since sullied with stone-stencilled graffiti.
Some, including myself, thought it should be obliterated to return the crater (left) to its natural form, but as some of it was clearly the work of Algerians from Ghardaia, others argued that, as foreigners, it was not our place to be meddling with local ‘Kilroys’ wanting to lift their leg on the place. And at least the loose stones were not permanent. Maybe someone else will do the right thing.
A dust haze had drifted up the valley that day, reminding me of the near disaster (from a visibility PoV) we’d had on the Eclipse tour in Niger back in 2006. Undeterred, Salah leapt back down to the canyon floor like a rubber gazelle where sure enough, a fresh goat stew was bubbling on the coals.
The following day we emerged from the Tafrakerk canyon at Aguelmam Rahla guelta (right) where we were in a little too much of a rush to wash off the dust of several days, much to the displeasure of Mohamed. He was quite right, we should have filled up and taken a bucket elsewhere, this waterhole is a key point for nomads topping off their goats prior to collection by Arab traders coming in from In Salah, two days drive northwest. A mile away, the terminal dune of the Erg Teganet (right) made a great backdrop to our camp as well as a challenge for some next morning, while I wandered around looking for the tombs I recalled seeing clearly on Google Earth a while back (left). More on tombs here.
After lunch we continued for half a day up the sandy Teganet oued (right) in the direction of Bir Outene at around 200km (see map). Here we had a day off waiting for the cars to arrive, as we’d saved a day taking the new route to the crater.
We sat around, moving with the shade while reading our books or Kindles until the late afternoon brought the distinctive hum of 4WDs churning up the river bed in low range. Too late to pack up now, one of the drivers had a guitar and later that evening around the fire we listened to him and Mohamed drumming on a plastic water can. Then as the sands sucked in the cold we headed for our dispersed camps. It was an early start next morning for the long run to Mehajibat dunes and another day’s drive down the TSH to our Hoggar base camp. More about that here.
From the back: me, RobUK, ‘Rick’, Steve, Sharif, Mohamed, Halil, Salah, Ahmed, Rob, Mike, Hannah, Diane, Tayeb, Loukmane, Said.
Immidir practicalities Tam-based Ben Kada agency had never run- or probably even heard of the crater route before, so I presume they took it upon themselves to travel up to Arak, track down Mohamed and his crew and ascertain that they could lay on the gear and knew the way. Ben Kada drivers dropped us off with the caravan and picked us up 11 days later, leaving it to the Arak guys to do the job.
We ate around 7.30, just around dawn and walked between 15 and 25km a day (10-15 miles), which was plenty given the terrain at times, although lunches were often 2 hours long. Most of the time we did not travel with the caravan and often took detours which the camels did not or need not follow. Sometimes we travelled with the kitchen camel and Tayeb the cook who prepared lunch, very often the best meal of the day. Breakfast was lean: tea or coffee, bread (baguettes or tagela), a solid block of marg, jam and Vache. As suggested beforehand, a couple BYO muesli or instant porridge. Once we had pancakes or French toast (eggy bread) or omlettes. Many carried day snacks, though I mostly went without as I had some weight to spare but was pretty hungry at most meals. Hot drinks, peanuts and biscuits were laid out soon after we arrived at the camp – most welcome – and dinner was ready 2 hours later: soup followed by a muttony stew, sometimes with pasta or cous cous or rice or bread, plus dates or oranges – and glasses of tea later. Most were asleep by 10pm.
Once water was taken from gueltas we filtered, though we all agreed it was more to get rid of unsightly sediment than microbes which might make us ill. We drunk enough untreated water from other sources and no one got ill. The sediment makes filters clog up within a litre or two so the uncleanable ‘squeeze bottle’ type got blocked early on, while the cleanable Katadyn and MSR ceramic core jobbies carried on working with regular cleaning.
Most of us had small blisters by the end and could do nothing about them except plaster them and keep them clean. No one’s walking was really affected; I had a really raw small toe but that recovered well enough on the 2-day drive to Hoggar. I had a feeling my feet swelled up after a few days which may have led to this – thinner socks did the trick until they wore out. Interestingly Bermuda Rob did the whole walk in a $70 pair of Nikes – they survived, were very comfy and he had no blisters! There were no other injuries even though we worked out there had been no less than 4 million opportunities to miss a step and sprain an ankle
Most found it got pretty cold around 6am: the mats supplied were pretty thin but once I recalled we had them, the extra blankets laid on were a great help with warmth (under or over).
The cook spotted one small, harmless snake on the trail which he killed without thought. Some were surprised by this, but desert dwellers have a different attitude to these and scorpions (none seen).
As on previous occasions, the route of our camel trek through the Immidir will rest a day at Aguelmam Rahla, a reliable waterhole at the mouth of the Oued Tafrakrek canyon (blue line on map, left) where the Tissedit plateau drops down to meet a band of dunes. I’d been wanting to make a diversion here since scanning Google Earth a few years back and noticing the innumerable pre-Islamic tombs (‘PIZ’) in the area (below).
Looking again on Google Earth some time later, less than an hour of nosing around revelled three dozen keyhole, antenna or crescent tombs within a few kilometres of the waterhole. I didn’t bother counting the less distinctive ‘mound’ tombs. In fact the proliferation of tombs here isn’t so unusual given the topographic features already listed: edge of a plateau, former river mouth, band of dunes – all common factors adding up to a Neolithic occupation site.
On the first crater tour in 2007 we walked along the base of the dunes, northeast from Aguelmam Rahla, and discovered several grinding stones and other artefacts at the foot of the dunes. And in 2012 one of us came across a near intact pot (left) at the foot of a dune as well as napping (stone tool chipping) sites.
There’s something compulsive about Sahara tomb spotting on Google Maps, searching the featureless desert floor for the clear signs of prehistoric human activity. Once out there it gives a purpose to a journey that’s otherwise just agreeable recreation and adds a hint of treasure hunting. It reminds you that the Sahara of 6000 years ago was not a desert, but a much less arid savannah. As mentioned in the Mark Milburn book review, among others, KenGrok has spent hours and years scanning and collating Google Earth’s imagery to identify unusual things, including pre-Islamic tombs in the Sahara. In 2019 Google erased his work but it seems his baton has been picked up by ‘syzygy‘ on Google Earth Community.
Often this fascination and excitement falls a little flat on actually finding a tomb on the desert floor. On the 2012 trip I was excited about finding a huge antenna tomb that lay close our path on Day 6 or so. On GE (above) the massive structure with a ring-angle span of over 300m looked amazing, but by the time we tracked it down it (left) was too big to appreciate from ground level. My group seemed to say… ‘and the purpose if this diversion was…?’. ‘Flying’ over these tombs on satellite imagery, like Peru’s Nazca lines, is how they’re best appreciated.
FYI: Google Earth was the original wonder but resolution is comparatively poor, at least in the Sahara. ZoomEarth offers a live view, but when you zoom right in appears to use the same superior resolutionj imagery as (Microsoft) Bing Maps Aerial.
How old are these ‘pre-Islamic’ tombs? Well in the central Sahara I’d say the Islamic era began to have an impact a couple of hundred years after the Arab Conquest of North Africa between AD 647–709. I imagine this swept like a tide west along the south Mediterranean coast, down the Atlantic to present-day Mauritania and then ‘eddied’ back west towards places like Timbuktu. Other eddies may have spun off sooner to places like Ghadames in Libya, following trans-Saharan trade routes into the interior.
Chances are these tombs, like the huge keyhole on the right in the Immidir (middle left of the picture; some 60m across), are only around 3000 years old, maybe double that. That means they followed the apogee of rock art some 6000 years ago following a climate change (the ‘Humide’ in the image below) which briefly repopulated populated what is now the Sahara. By this time megalithic tombs became widespread across the ancient world, most spectacularly in ancient Egypt.
What’s interesting is the orientation of these tombs is almost always towards the east; you may have noticed that by looking closely at the link above. Be it a keyhole with a ‘walkway/slot’ or the open arms of an antenna, the orientation is always eastwards within the range of the rising sun, according to the diagram, left, with concomitant suggestions of ‘rebirth’ and afterlife.
You don’t have to venture into the deep Sahara to see keyhole tombs. In southern Morocco, just a short distance from Erg Chebbi and three miles west of Taouz, on the west side of the Oued Ziz are a cluster of tombs. Like Aguelmam Rahla they’re situated on the edge of a plateau and by a former big river as well as an erg – and not all with entrance ways pointing east.
Below, a curious structure on the Oued Tagant valley midway between Tam and Djanet. And below that, another in the Hoggar, just southeast of Assekrem. I’ve seen these elsewhere in southern Algeria but their meaning is unknown. The guides and old Saharan expeditions just call them ‘tombs’ but they look different and newer than PIZs. More here.
Distribution of ancient stone structures in the Sahara. More here with kmz download
Sahara Overland 
