
From a terrific article in the NY Times (see link below). The Falls are so beautiful, but 50% of the water is diverted for power generation. In other words, they've taken away 50% of the water that used to tumble over one the world's greatest natural wonders. Imagine what it must have once been like.
http://www.nytimes.com/2011/10/30/opinion/sunday/annie-leibovitzs-pilgrimage.html