There are a number of factors to consider when determining the tallest waterfall one could survive falling into, such as the height of the waterfall, the speed at which one is falling, and the depth of water at the bottom of the falls. Generally speaking, however, experts agree that anything over 200 feet is too tall to survive.
At Niagara Falls, for example, which has a vertical drop of 167 feet, only around 20% of those who go over survive. And even then, most survivors suffer from severe injuries such as broken bones and internal bleeding. So if you're thinking about taking a plunge off any waterfall taller than 200 feet, think again - it's simply not worth the risk.