The Great Falls of the Missouri River are a series of waterfalls on the upper Missouri River in north-central Montana in the United States. From upstream to downstream, the five falls along a segment of the river are: Black Eagle Falls () Colter Falls () Rainbow Falls () Crooked Falls, also known as Horseshoe Falls () Big Falls, also known as the Great Falls, () The Missouri River drops a total of from the first of the falls to the last, which includes a combined of vertical plunges and of riverbed descent. The Great Falls have been described as "spectacular", one of the "scenic wonders of America", and "a major geographic discovery". When the Lewis and Clark Expedition became the first white men to see the falls in 1805, Meriwether Lewis said they were the grandest sight he had beheld thus far in the journey. The Great Falls of the Missouri River were depicted on the territorial seal of the Montana Territory, and later on the state seal of Montana in 1893. Names of the falls The Mandan Indians knew of cataracts and called them by a descriptive (but not formal) name: Minni-Soze-Tanka-Kun-Ya, or "the great falls." The South Piegan Blackfeet, however, had a formal name for Rainbow Falls and called it "Napa's Snarling." No record exists of a Native American name for any of the other four waterfalls. Four of the five waterfalls were given names in 1805 by American explorers Meriwether Lewis and William Clark. Both Lewis and Clark named Crooked Falls in their journals. Clark named three of the remaining waterfalls on his map: "Great Falls" (which retains its name to this day), "Beautiful Cascade" (now called Rainbow Falls), and "Upper Pitch" (now known as Black Eagle Falls). "Beautiful Cascade" was renamed "Rainbow Falls" in 1872 by Thomas B. Rogers, an engineer with the Great Northern Railway. Colter Falls received its name from Paris Gibson, in honor of John Colter (a member of the Lewis and Clark Expedition). Black Eagle Falls is named for the black eagle which built a nest in a cottonwood tree on an island in the middle of the falls. It is not clear when the falls lost their original name of "Upper Pitch," but they had acquired their modern name by at least 1877. Geological history The Missouri River lies atop the Great Falls Tectonic Zone, an intracontinental shear zone between two