These are the so-called American Falls.  This picture is taken from Goat Island, on the American side.

Here are the American Falls again, but from the Canadian side of the river.  Oh, and there's a friend of ours in the foreground.

The other falls, the ones which bridge the American and Canadian side of the river, are called the Horseshoe falls. 
Here they are, shrouded in mist, from Goat Island...

And here they are, from the viewing tower on the Canadian side. 

Finally, the American Falls one more time with two spray-induced rainbows in the foreground.