This is the first of two very similar but distinct images of the Rock of Ages and Cave of the Winds complex of Niagara Falls as they appear when illuminated with colored lights.

The description states:
NIAGARA FALLS BY ILLUMINATION
This new enhancement of America’s beauty resources is nothing more than the Falls, under flood lighting for four hours each night. Their own power has been taken from them, brought under the control of man, and then turned back upon the power creator itself, and we get a new beauty, ten-fold greater than any beauty known at the Falls before man took hold to conquer them for service.
–This version of the image appears to be the older of the two, primarily based on the quality of the production. It also focuses more on the background detail, highlighting the walkway that existed near the base of the falls.
This image likely dates from the 1930s.