Five separate waterfalls strung along ten miles of the Missouri River — Black Eagle, Colter, Rainbow, Crooked, and the Great Falls themselves. Together they drop the river more than 600 feet. In June 1805 Lewis and Clark spent 31 days hauling their boats and gear around them over the prairie, the single hardest stretch of their journey.
The falls are best seen from the Rainbow Falls and Ryan Dam overlooks, both reached by short drives north-east from the city. Ryan Dam (the original Great Falls) is the most dramatic, especially in spring runoff. Bald eagles are commonly visible from any of the overlooks.