There's a waterfall in Brazil that's for true adventurers only: it appears to "swallow" people whole beneath a rock and spit them back out on the other side. Pedra que Engole, or "a stone that swallows," is in Trindade, Rio de Janeiro, and it attracts people not only for its beautiful views along the river, but also for its adrenaline-increasing activity.
Once you reach the rock formations after a bit of a hike, you'll come across the small waterfall that sucks you in with its rapidly gushing water. People scoot right up to the opening between the stones and push themselves downward before they completely disappear beneath them. It looks like they're either crushed or trapped underneath the rocks, but they come out safely on the other side a few seconds later. Just watching videos of people doing it is enough to get your blood pumping!