This photograph was developed from glass plate negatives. It was taken in 1909 when the American Falls of Niagara Falls froze. A few brave souls actually walked across the frozen falls. Note the old camera in the picture.
A bit of information: On six reported occasions (1883, 1896, 1904, 1909, 1936 and 1947), the water flow over American Falls has been totally blocked by ice and ceased to fall. ~ Source: The Weather Almanach
author of the Dark Birthright trilogy