I did caving once, the kind where at certain points you squeeze through tight areas going down.. I was somewhat ok with it at the time, but shortly after finishing I became progressively more freaked out about what I had been doing, and the possibilities of what could have happened. I never thought about trying it again.
The most dangerous part of this trip though, was probably being in Abkazia at all. :)
Wow, I could never do it. I was freaking out just watching it, lol.