Falls of the Ohio - here's a link
There is a lot of history, natural and human, relating to these falls. Clarksville, Indiana is the first American settlement of the Northwest Territory. The riverbed is made up of a 365 million year old coral reef. That is Louisville, Kentucky in the background. Louisville became a thriving city due to the portage needed to circumvent the falls. In the movie, "How the West Was Won" a family was nearly wiped out when they mistakenly took their raft through the worse part of the Falls of the Ohio.