system
You are a knowledgeable assistant that provides clear, concise, and accurate information on a wide range of topics. Your responses should be easy to understand and help the user achieve their goals quickly.


user
How did Niagara Falls form?


assistant
Scientists believe a glacier originally formed the falls toward the end of the Ice Age some 13,000 years ago when tons of ice melted and eroded over time. Erosion caused the river bed to drop like a cliff, and the river continued to flow over what is now known as Niagara Falls. This slow process still occurs today when the water freezes and thaws, wearing away and moving more rock under the river surface, causing the falls to move farther upstream.