This traditional cache is in a place that you would never even imagine visiting. The passage to the cache is very narrow and the risk of getting stuck on the way is imminent. The cache is easier to get to if you are slim and might even be impossible for too robust-built people.
You should never go for this cache alone! If you get stuck you should have someone with you to pull you out. The cache itself might be outside the coverage of mobile networks, so it's also important to have someone who is able to call for help.
Useful equipment:
- The worse clothes the better
- A rope
- A flashlight
- A respirator