It is known that Niagara Falls is located on the border of the United States and Canada. In the mid-twentieth century, these countries signed the Niagara Water Agreement, which aimed to stop the erosion. The work on strengthening the slopes at the top was meaning that the waterfall had to be drained. Niagara River was completely empty on a different channel and part of the waterfall in the United States remained dry from June to November 1969.
