Terelj's Crystal Cave(s)

I tried hard. Very hard. To find more caves than the 100 Monks Cave... but it was difficult. After long period of Internet searching, I settled on visiting the Crystal "cave", even if it was just an abandoned man-made mine. It was nearby though, also in Terelj, and not 17 hour drive away so that's a positive :-) But my first guide was unable to take me to this place, so I looked for another guide company. A got the whole deal, the driver, the guy who speaks English to me, and the local guide who knows where the mine is :-)

Except ... maybe not. After hiking for a long time in an admittedly beautiful valleys among spectacular rock formations in sunshine but also freezing wind, the guide couldn't find the mine. We did find it, eventually, after several calls to people in the know, and more walking.

Except ... maybe not. This wasn't the Crystal cave I had found from the Internet. It was a crystal mine for sure, and had the crystals around it to prove it. It was also made by Chinese like the other one. However, it was a different mine, in a different location. That's of course alright, I still got a crystal mine :-)

Except ... I didn't. We were standing next to the hole, with no ropes or other ways to enter the vertical shaft down to the mine floor 10+ meters below. So we couldn't actually go inside. The other mine would have been horizontal.

Anyway, it was a very nice walk in the mountains, and I saw some smaller cavelets or mini-caves along the way, and spectacular red rock. And met a very nice family living in a Ger (yurt tent), and had a superb lunch, though of course all meals are probably superb after a roundtrip 10km walk in the mountains :-)

So I'm happy, after all :-) 

Here's the mine I was originally trying to get to:

The West Crystal Cave, again in Terelj National Park. This is an old mine, so man-made underground tunnel. I have not been here, but pictures show nice icicles etc. It seems possible to enter this place. The coordinates are N 47.876958 E 107.372582. The location is west of the main road going through Terelj. You will have to hike kilometers from the road to the top of the ridge. See these links for more information: Google Maps, Lonely Planet, Monrevetours, Monrevetours photos on Flickr, Facebook tour advertisement.

(Photo by Monrevetours in Flickr)

And here's the mine we ended up in:

The East Crystal Cave, also in Terelj National Park. East of the main road this time. This is also a mine, and one that I visited. Or at least stood on entrance to it. You can't enter without ropes, the mine is a tunnel straight down until it branches off horizontally. I hiked 5 kilometers (one-way) from nearest road to get here. The coordinates are N 47.912347 E 107.48860. 

The other caves I saw are here:

A tiny roof cave in boulders (or cavelet), again in Terelj National Park. The coordinates are N 47.910005 E 107.48736. The sheltered area is approximately 2.5 m.

FWIW, I also looked at a crack in one of the cliffs (coordinates N 47.903264 E 107.47713) but in the end determined that this was too small to be listed even as a cavelet.

A roof cave in a cliff face, used as a cow shed of a farm. Again in Terelj National Park. This seems more like a real cave, though as it was on someone's farm, I did not enter it. The coordinates are N 47.889781 E 107.46194. The sheltered area is longer than 5 m, but since I was not next to the cave, I was unable to measure this exactly.

Here are some of the other views from this walkabout:

For more caves in Mongolia, read the my summary article.

Read the full Planetskier series at planetskier.net, urban exploration stories from theurbanexplorer.net, and other underground stories from planetcaver.net, or all blog articles from Blogspot, TGR. Photos and text (c) 2025 by Jari Arkko, except where otherwise indicated. All rights reserved. 

Mongolia: 100 monks in a cave

Mongolia caving, yay! Freezing temperatures and beautiful red granite rock of the Terelj national park near Ulaanbaatar, what's not to like? On my way to Mongolia I run into to other travelers from Finland, and they were able to join me on the Sunday excursion to Terelj. Together with a guide we headed to the 100 ламын агуй, or the 100 Monk Cave. Besides caves, we also looked at turtle-shaped massive rocks, world's largest horse rider statue, local population's ger (yurt) tents, and snowy mountains. The only question is if the cave will fit 100 monks as advertised ...

It was surprisingly difficult to find visitable caves in Mongolia. But since I was in Mongolia for the skiing, I also wanted to visit a cave... as this would be my 32nd country that I'd have been in caves at. I finally managed to find one, as our guide Nomuundalai Batdelger remembered a cave in the Terelj park. I had found many caves from Mongolia, but most of them were far away from Ulaanbaatar, and the short trip and the winter didn't really allow travel. For instance, travel to the Khoid Tsenkher cave would take some 17 hours by car to western Mongolia. By the way, I have a separate article about the caves in Mongolia for future reference if anyone wants to visit the caves that are publicly known.

The 100 Monk Cave is sitting next to the road through Terelj, so it is easy to access. We went first around the large rock to find where the cave entrance is, but the main cave entrance turned out to be on the front facing the road. You'll just have to climb up a bit. The entrance to the cave is a bit slippery, I think the rock has gotten smooth due to the many visitors, and of course the winter doesn't help the situation. I was afraid I'd fall if I was higher up the cave entrance, as it was sloping side ways up. Further inside the cave it was easy, as the slope was less steep and the surface was less slippery. There's two entrances to the cave, the lower and the upper, but at least I was unable to use the lower one, as the step down from that entrance was a bit sketchy. 

Then there's a side cave, which isn't really a proper cave as the rock just forms a small roof over the side of the big rock, so you can stay protected from the rain if you need to.

The main cave continues for 28.26 meters, so it is quite sizable for us Finns who have been used to tiny caves :-) Inside the cave, as is the tradition in Asia, people have brought small gifts: candles, cookies, a small toy horse, paper money, ... and even gold-colored goblets. While the entrance is just rock, further in the cave there's sand and dirt on the floor as well. The cave gets pretty low though in the end.

I loved the view out of the cave to the mountains on the opposing side of the valley. An example in the opening picture on this article.

So what about the 100 monks? Some doubts have been expressed if you really could have had 100 monks inside. Since I did a 3D scan of the cave, I got the length that was mentioned above, as well as the width that varies between 5 and 11 meters. If we take the average of those widths, we arrive at the floor space of about 225 m2. This is more than 2 m2 per monk, so assuming they are fine sleeping on a sloping rock, this should be plenty of space for the 100 monks to camp in :-) Definitely not just 10, as the sign next to the cave says. But also, 1000 would be too much.

About the 3D scans, I've been doing them with the iPhone's lidar, and using them to document caves. The scan was a bit troublesome this time though. My phone run out of battery in the middle of the process, maybe due to the -24 temperature in the morning. And then it run into some other issues, maybe software or just running out storage on the phone. I assumed the scans were lost, but it turned out that I was able to piece together a workable model from the two half-finished broken scans. That was a nice surprise! I used the 3D resulting model to draw maps (using the software I had written earlier), measure the length of the cave, and give an ability to look at the cave in 3D on your browser screen. More on this later in the article.

The cave is in these coordinates: N 47.8395200 E 107.3990359. There's a nice coffee and cashmere shop right by the rock outcrop, as well as a horse and camel riding on the other side of the road. The the side roof cave is at coordinates: N 47.839820 E 107.398632.

We also visited the Turtle Rock, a massive turtle-shape rock. Or a mountain, really. That too had a small cave-like space in a corner of the rock, in a crack between the different rock parts. To get to this crack, one has to climb up the right side of the rock until you find the crack. In the winter this was a bit challenging, as the snow and ice made again everything quite slippery. And the rock is very large. The coordinates for the Turtle Rock are: N 47.907703 E 107.422819.

Main cave pictures:

Here's the cave entrance from the outside, the cracking going horizontally up to the right:

Here is the 3D scan, turned into a horizontal map and some vertical cut-outs. Here's the plan view (horizontal) map:

And an example vertical cut view from point A. Note how the cave is slanted to the side.

The full map including all cut-outs is available in PDF format here. The 3D model can be downloaded in GLB format from here and Blender format here. You can rotate the model on your own browser screen by clicking on this link.

A screenshot of the model can be see below:

Fly-through in the model:

Views from the site:

Side cave pictures:

Turtle rock:

Lunch at a ger tent:

Tsingis Khan statue:

I also attempted to visit the (or rather "a") crystal cave nearby. More on that story in another article. And saunas and swimming in yet another article.

Read the full Planetskier series at planetskier.net, urban exploration stories from theurbanexplorer.net, and other underground stories from planetcaver.net, or all blog articles from Blogspot, TGR. Photos and text (c) 2025 by Jari Arkko, Grayden Prince and Hanna Mykkänen. All rights reserved. 

Mongolian caves

I visited Mongolia in February 2025, and of course wanted to visit some caves. It turned out to be a bit challenging, it is a large country with some of the potential caves too far away from Ulaanbaatar where I stayed, some caves would not be possible to visit in the winter, couldn't connect to the local caving association, etc. But I managed to visit one good cave and some tiny holes maybe not classified as caves, and one mine. But in this article I wanted to outline all the Mongolian caves I found out about, for others to explore if you happen to be traveling to Mongolia.

I have used four main sources for this article.

First, just a regular Internet search for caves (or agui/агуй) in Mongolia.

Second, Google Maps search was equally useful.

Third, the Mongolian Cave Research Association's page has a description of some of the caves they believe should be highlighted. Their page is here.

Fourth, a very nice article by Nils Vanwezer and others in Quaternary International that has among other things a detailed map of all caves in Mongolia:

(Picture from the article)

You can access the article from this link, and the full reference is:

Vanwezer, Nils & Breitenbach, Seb & Gázquez, Fernando & Louys, Julien & Kononov, A. & Sokol'nikov, Dmitry & Erdenedalai, Avirmed & Burguet-Coca, Aitor & Picin, Andrea & Cueva Temprana, Arturo & Sánchez Martínez, Javier & Taylor, William & Boivin, Nicole & Jamsranjav, Bayarsaikhan & Petraglia, Michael. (2021). Archaeological and environmental cave records in the Gobi-Altai Mountains, Mongolia. Quaternary International. 586. 66-89.10.1016/j.quaint.2021.03.010. 

The article doesn't have detailed information of all the caves shown in the map above, but does have information about 25 of them, so I have taken them into account as well.

Here's the list of caves and mines I found out about. First, there's my Google Maps sharable link with all the locations and cave names. 

What follows are descriptions of the caves:

1. 100 Monk Cave or the 100 ламын агуй, in Terelj National Park near Ulaanbaatar. The coordinates are N 47.8395200 E 107.3990359. This is the cave I visited, see the separate article. The length of the cave is 28.26 m.

2. There's a smaller 100 Monk Side Cave, again in Terelj National Park, just a roof/shelter cave on the southern side of the same rock the 100 Monk Cave is in. The coordinates are N 47.839820 E 107.398632. Also described in the same separate article. The length of the cave is approximately 6 m.

2. Some cave-like spaces on the Turtle Rock, also in Terelj National Park. The coordinates are N 47.9077036 E 107.4228194. Also described in the same separate article. The sheltered area is less than 5 m.

3. West Crystal Cave, again in Terelj National Park. This is an old mine, so man-made underground tunnel. I have not been here, but pictures show nice icicles etc. It seems possible to enter this place. The coordinates are N 47.876958 E 107.372582. The location is west of the main road going through Terelj. You will have to hike kilometers from the road to the top of the ridge. See these links for more information: Google Maps, Lonely Planet, Monrevetours, Monrevetours photos on Flickr, Facebook tour advertisement.

(Photo by Monrevetours in Flickr)

4. East Crystal Cave, also in Terelj National Park. East of the main road this time. This is also a mine, and one that I visited. Or at least stood on entrance to it. You can't enter without ropes, the mine is a tunnel straight down until it branches off horizontally. I hiked 5 kilometers (one-way) from nearest road to get here. The coordinates are N 47.912347 E 107.48860. See a separate article for this one.

5. A tiny roof cave in boulders (or cavelet), again in Terelj National Park. The coordinates are N 47.910005 E 107.48736. The sheltered area is approximately 2.5 m.

FWIW, I also looked at a crack in one of the cliffs (coordinates N 47.903264 E 107.47713) but in the end determined that this was too small to be listed even as a cavelet.

See the same separate article for both of these.

6. A roof cave in a cliff face, used as a cow shed of a farm. Again in Terelj National Park. This seems more like a real cave, though as it was on someone's farm, I did not enter it. The coordinates are N 47.889781 E 107.46194. See the same separate article again. The sheltered area is longer than 5 m, but since I was not next to the cave, I was unable to measure this exactly.

7. North Tsenkheri Cave, Khoit Tsenkheri Agui, or Хойд Цэнхэрийн агуй. This cave is 30 kilometers from Mankhan soum in the Khovd aimag (province), the coordinates are N 47.34736572 E 91.95670460. See these links for more information: Google Maps, Wikipedia, Mongolianature in Weebly, Mongolian Cave Research Association. There are cave paintings in this cave from 40 000 years ago.

(Photo by BatboldDorjgurkhem from Wikipedia, CC BY SA4.0)

8. Gurbanzeerdiin Cave or Гурван зээрдийн агуй. This cave is in Khanbogd soum, Umnogovi aimag. The coordinates are N 42.537500 E 107.357333. See there links for more information: Mongolia Touristinfocenter and the Mongolian Cave Research Association.

(Photo from Mongolian Cave Research Association)

9. Dayandeerkhiin Cave or Даяндээрхийн Агуй in the Dayanderekh National Park, in Derhiin Hüryee, Khovsgol aimag. The Google Maps links says this place is permanently closed, there's some confusion in that there's two maps entries, one for the park with cave pictures, and another one for the cave with park pictures. The more likely place out of the two has coordinates N 50.574684 E 102.058229. The length of the cave is 224 m, one of the longest in Mongolia.

For more information see these links: Google Maps link 1, Google Maps link 2, Mongolian Cave Research Association.

(Photo from Mongolian Cave Research Association)

10. Tsakhiryn Agui caves in Khaliun at the Govi-Altai aimag. There's six caves (1, 1b, 2, 3, 4, and 5). Their coordinates are N 45.845921 E 96.28559, N 45.845921 E 96.28559, N 45.849919 E 96.27474, N  45.849911 E 96.27557, N 45.854959 E 96.28183, N 45.853443 E 96.27914. More information from the Vanwezer article.

11. Irvesiin Agui, Khaliun at the Govi-Altai aimag. The coordinates are N 45.853218 E 96.27684. More information from the Vanwezer article.

12. Nuramt Tsakhir Agui, Khaliun at the Govi-Altai aimag. The coordinates are N 45.878726 E 95.79398. More information from the Vanwezer article and the Max Planck Institute page.

(Photo by Max Planck Institute)

13. Khongil Tsakhir Agui, Khaliun at the Govi-Altai aimag. The coordinates are N 45.878231 E 95.80328. More information from the Vanwezer article.

14. Gazar Agui caves in Taishir. There's 13 of these caves (1-13) and their coordinates are N 46.763898 E 96.2194, N 46.692067 E 96.23888,  N 46.6921 E 96.23852, N 46.76562 E 96.21839, N 46.76562 E 96.21839, N 46.76562 E 96.21839, N 46.762741 E 96.22803, N 46.764154 E 96.21956, N 46.765564 E 96.21236, N 46.765564 E 96.21236, N 46.764151 E 96.21946, N 46.764151 E 96.21946, N 46.763367 E 96.20794. More information from the Vanwezer article or read about the rock art in Gaza Aqui 1 and 13 in another Vanwezer article at the Archaeological Research in Asia.

15. Saalit Agui caves in Bayan-Ondor. There are three caves (1, 2, and 3). Their coordinates are N 44.784024 E 99.04367, N 44.782081 E 99.04735 and N 44.786055 E 99.04151. More information from the Vanwezer article or about the rock art in the other Vanwezer article.

16. White Cave or the Tsagaan Agui in Bayan Lig, at the Bayankhongor aimag. The coordinates are N 44.712028 E 101.170389. For more information, read Wikipedia, Mongolia Guide, academic article at Antiquity, another academic article at Archaeology Ethnology and Anthropology of Eurasia, or the Mongolian Cave Research Association's page. There's also a 3D tour at the PaleoMongolia page.

Wow what an interesting looking cave!

(Photo from Mongolia Guide)

17. Taliin Cave, Dariganga, at the Sukhbaamar aimag. The coordinates are N 45.590278 E 114.500572. More information can be found from the Mongolian Cave Research page or Wolfgang Pfriemer's photos. At 240 m, this is the longest cave in Mongolia according to Wikipedia.

(Photo by Wolfgang Pfriemer at ipernity)

18. Lobonchombiin Cave in Aguy-sume, at the Omnogovi aimag. The coordinates are N 42.588394 E 107.825322. Read more about this from the Mongolian Cave Research Association.

(Photo by Mongolian Cave Research Association)

19. Tsagaandeliin Cave in Airag, at the Domogovi aimag. The coordinates are N 45.625528 E 109.107056. Read more about this cave from the Mongolian Cave Research Association.

(Photo by Mongolian Cave Research Association)

Read the full Planetskier series at planetskier.net, urban exploration stories from theurbanexplorer.net, and other underground stories from planetcaver.net, or all blog articles from Blogspot, TGR. Photos and text (c) 2025 by Jari Arkko. Some photos are from various sources, such as Wikipedia, Wikimedia, Flickr, or academic articles. All rights reserved per original source.