Perhaps you would have your picture taken in front of a screen with a picture of the Falls on it or purchase a cabinet card of the Falls.
Or, you might have picked up a little Tru-Vue viewer so you could visit again and again, from the comfort of your home.
Can you just feel the mist on your face? I get such a kick out of the great 3D effect of these old viewers. Sometimes, colour just spoils the mystery of good photography.
The earliest item I have seen so far regarding Niagara Falls is a book dating from 1815. You can see it here. Too dear for me! (I was thrilled to be able to take a picture inside the viewer. How cool is that?)