The true statement about Niagara Falls is:
More water rushes over Niagara Falls than any other waterfall in the world.
To elaborate on the other statements:
- Niagara Falls is not the tallest waterfall on Earth; there are many taller falls, such as Angel Falls in Venezuela.
- The falls are still used to generate electricity, with hydroelectric power plants in operation.
- While erosion is occurring, estimates suggest that Niagara Falls will take thousands of years to significantly change, not just 500 years.