This image shows both of the large cascades that make up the Niagara Falls complex, as seen from the Canadian side of the border.
The description states:
THE AMERICAN AND HORSESHOE FALLS
Niagara Falls, Canada
Seen from the Canadian side of Niagara
–The postcard was used and is dated 1952, which is consistent with the models of cars seen parked in the photo. The link above has another photo of this same area as it now exists, and the viewing area is still present, but much more fully developed.