This is the Excalibur, a climbing wall at the Bjoeks Climb Center in Groningen, The Netherlands. At a whopping 121 feet tall and with an overhang of 36 feet, it's the tallest climbing wall in the world.
I mean, sure, there are clearly much taller structures for climbers to ascend in nature, but there's something about this unnaturally curved tower that just looks crazy. Maybe it's the fact that it just sticks up out of the ground in a flat area that makes it look so intimidating. But whatever it is, one thing's for sure: I won't be climbing it anytime soon.