This image is taken from a similar, but from the Rainbow Bridge, further downstream from the viewing area in the previous photo. It is composed to make the falls look more wild and natural, as the only obvious modern presence is the tour boat in the left center of the photo. This boat is the famous Maid of the Mist.
The description states:
NIAGARA FALLS FROM RAINBOW BRIDGE
Niagara Falls, Ontario, Canada
A breathtaking sight of Mother Nature’s great masterpiece. Niagara Falls, as seen from man’s great accomplishment, Rainbow Bridge, a beautiful combination of Power and Art.
–The bridge was built beginning in 1939 and completed in 1941 as a replacement for the older Honeymoon Bridge which collapsed from an ice jam on the river.
This card was used and is dated 1956.