Visit the beautiful Victoria Falls in Africa between September and December. Personally, I recommend the Zambian side.
During the dry season the Zambezi River waters are relatively low.
So low that you can actually walk across most of the 1 km wide Upper Zambezi River.
This is where it gets interesting. At the top of the falls an eddy current forms at Devil's pool. The current flows upstream due to the geology of the river and actually appears to lack any current whatsoever. Translation: if you jump into the river at this one spot, you won't be swept over the edge.
So without further a due footage of the craziness that is Devil's Pool.
You may have noticed that I am not in the video. Well, our group opted to have our pictures taken instead, which you can view in this post. But, the above video captures the awesomeness of what we did. We were all a bit surprised the eddy current wasn't more obvious. Which makes you wonder how anyone ever figured it out in the first place. Really, all that is between you and and a 100+ m drop is a couple of feet of rock. Amazing!