These famous falls are located in southern Africa at the border of Zambia and Zimbabwe. Victoria Falls are considered the largest (not tallest or widest) in the world because when measured by width and height, they form the largest sheet of falling water.
I've been to Niagara Falls more times than I can count, and it is ALWAYS simply incredible. I've stood by the falls for hours, until soaked by the spray. I've also been there when the smaller section (The American falls) was frozen.