Niagara Falls is not exclusively an American landmark. It is a transboundary natural wonder straddling the border between the United States (New York) and Canada (Ontario).
The falls comprise three sections:
Both nations operate parks, viewing areas, boat tours (Maid of the Mist / Hornblower), and illumination. The Niagara River forms the international boundary. The 1909 Boundary Waters Treaty governs water diversion for hydropower while preserving the falls' scenic integrity.
So while Americans proudly claim Niagara, it's truly a shared heritage site—one of the world's most famous binational landmarks.