Only 10,00 years old
Evidence showed that the beginning signs of Niagara Falls go back 18,000 years ago. The formation that we can see today was completed roughly 10,000 years ago. That’s about 133 lifetimes ago, based on the 75-year lifespan average. However, this is nowhere near the age of the oldest natural rock formations in the world.
To put this in perspective, the Giant Causeway Columns were formed more than 60 million years ago, or about five million years after dinosaurs took their final steps on Earth. This just goes to show that natural forces are a lot more powerful than we give them1 credit for!