Most people probably assume you can't set a waterfall on fire. There would be every reason to believe that, based on common sense. But you should have seen The Yosemite Firefall at Yosemite National Park. Until 1968, this was an event during the summer that created stunning visuals for visitors. The owners of a nearby hotel poured hot embers from the top of the falls, and as they came down, it looked like a fire waterfall.
It was a neat trick, and tourists flocked to view it. But eventually, it attracted too many! As a result, the event was ended forever.