While I was there I noticed one person's office had a kid's drawing posted on the door which was (for the most part) pretty standard: One green tree, one house with a four-pane window, two smiling stick figures, but what made me smile was the giant red cliff scribbled into the background with a third stick figure climbing up it.
Every few nights my friends and I watch for tiny lights that flash around high up on the canyon walls. The lights are from the headlamps of extreme rock climbers who climb these walls for days at a time and actually set up camp overnight on the face of the cliffs. One morning I scoped the wall with some binoculars and spotted a red hanging tent, called a portaledge, dangling two thirds of the way up on a 1,200 foot wall like a wildly misplaced sack of potatoes. Zion National Park is a world-renowned destination for big wall climbing with some walls rising over 2,000 feet.
Here's a picture from Red Desert Adventure's site to give you an idea of what Zion's climbing walls look like:
Crazy. I can't even tell how the climber in the left photo can find a grip; that wall looks pretty smooth to me.
If you want to see some more extreme climbing photography (including a look at what those portaledges are like) check out this guy's photos here.