I was going to say this. I mean, we freak out at the idea of doing it now. Imagine some guy 1000 years ago who found a crevice... in the dark... and decided to crawl through it. That... both impresses and terrifies me.

Now overlay that with the belief that your are literally descending into the underworld.[1]

It must have made for a very transformative experience.

[1] https://en.wikipedia.org/wiki/Xibalba