The Tuwaiq Escarpment runs for about 500 miles down central Saudi Arabia from al-Qassim to the Rub al-Khali. It's about 20 minutes west of the edge of Riyadh and is pretty sheer near the city. The first time I saw it was when we were driving out to go four-wheeling and I had no idea it was there. I love it.
But it's a pretty big impasse if you're trying to get from Riyadh (or Diriyah before Riyadh) to Mecca, and lots of people were trying to do that. There's a road now, about thirty years old, that zips you up and down, but before that you had to go south toward al-Kharj and then head west to access (I believe) a wadi that cuts through the escarpment (around Dirab - I need to explore this one more). That's a much longer trip on a camel.
So some enterprising people built camel trails down the escarpment. There are several of them although most have crumbled away. But the one you can see best, that expats call Camel Trail #1, is actually climbable all the way down and that's what's in the photos below, if you see a trail. We haven't done the hike yet but I plan to very soon. It has a bit of a developed area on top with some stone picnic benches and more people go there. The road is also fairly good, except for the washed-out parts. This one is south of the main road.
North of the main road, you can try to find at least three more. We've been to the top and bottom of several of these and I don't think any are still climbable, but we'll keep exploring. The photos below with the pinnacle are near camel trail 4. The pinnacle is called Faisal's Pinnacle and you can climb it. We hoped we could climb part of camel trail four if we got to the bottom, and we had the coordinates for the trail, but I don't think it's possible. Also, there really aren't a lot of roads along the bottom of the escarpment but it's very interesting to drive down there. No matter what, standing at the bottom of the escarpment or the view from the top is worth the trip. If you go along the top, there are fenced-off quarries but camel trail 3 (or the spot marked that but there is not a trail left maybe but hiking down to the edge is very cool) is not fenced.
These are all very conveniently marked on google maps if you want to try finding them yourself. Also, there are geocaches.