Rock climbing is a favorite extreme sport of daredevils everywhere. But how about crane climbing? And how about doing it with no safety equipment whatsoever? And that’s not even the scariest part of this clip.

These three guys climbed up a towering crane in the middle of the city with no ropes or anything. Then they ventured out onto the boom. And as if that weren’t enough, one of them started doing pull-ups on it!

I’m not terribly afraid of heights, but this video still made me squeamish. These guys have balls all right, but it’s a wonder someone didn’t end up scraping them off of the ground below.