This vintage Niagara Falls postcard shows Bridal Veil Falls on the American side with the Cave of the Winds behind it.
Although this postcard is newer and brighter than the Cave of the Winds postcard, it is still older than 1920 because we see the bridge to the Cave of the Winds allowing people to walk behind the falls.
Luna Falls, which forms the Bridal Veil, is separated from the main part of the American Falls by Luna Island.
The water being carried over the edge goes well beyond the face of the cliff due to the force behind it. The excavation by the spray and frost of the softer rocks below created a passageway behind this Fall known as the Cave of the Winds.
As mentioned in the other postcard page, this passageway was closed after 1920 due to a rocks slide making it unsafe. Only the Victorian visitor to Niagara Falls was able to experience the Cave of the Winds. Perhaps you have a grandparent that can tell you about that.