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.
Great shot of both the Canadian "Horseshoe" falls (bottom) and the American falls (upper right). Water from Lake Erie flows down The Niagara River, drops down Niagara Falls, flows down the Niagara Gorge and out to Lake Ontario .