Any sixth grader worth his salt knows the expedition of Lewis and Clark and can point to Shoshone tribeswoman Sacagawea on the golden U.S. dollar coin. What many don’t know is the peril all three encountered throughout their journey, the power plays inherent in the overall intent of the expeditions, as well as the scientific and economic discoveries that resulted.

President Thomas Jefferson commissioned a campaign to be made across the United States through the newly acquired Louisiana Purchase territory, all the way to the Pacific Coast. Jefferson was keen on explored his new land, and also on finding a practical route across the Western half of North America. Included in his planning was the intent to establish a firm American hold on the country’s new addition before European or British powers could intervene and to make friends with Native American tribes occupying the area.

Jefferson hand-picked U.S. Army Captain Meriwether Lewis and his good friend, frontiersman William Clark. Officially titled the Corps of Discovery Expedition, the camp of 33 set out May 14, 1804 from St. Louis, Missouri, on the eastern bank of the Mississippi River aboard a 55-foot-long keelboat and two smaller pirougues.

Historians and data from the journey describe Clark as spending the majority of his time on the keelboat, making maps and notes and charting the group’s course. Lewis was often seen on dry land, noting rock formations, soil types, animals and new plant life.

The tour followed the Mississippi through settlements in present-day Kansas City, Missouri, and Omaha, Nebraska, before they crossed the Great Plains. Their journal entries noted the abundance of beavers, elk, deer, and bison. The crew formed alliances with two dozen Native American nations, resulting in essential guidance through uncharted and unfamiliar territory for Lewis and Clark. The native people were often given gifts and promises of good will if they granted passage to the Corps.

In late 1804, tense relations with natives in modern-day Washburn, North Dakota, nearly escalated into a fight. The Mandan tribe and the expedition leaders eventually fell back and Lewis and Clark came to meet a young French-Canadian fur trapper named Toussaint Charbonneau and his young wife Sacagawea, of the Shoshone tribe. For the rest of their stay, Charbonneau acted as a translator and liason between the Americans and the Mandan, eventually ending in the sharing of a Mandan peace pipe. Sacagawea and her young son agreed to accompany the expedition on the rest of the journey, acting as a diplomatic party and translator on behalf of the Corps.

The team followed the Missouri River, Snake River, and Columbia River into what is now Portland, Oregon, spent a harsh winter, then began the long trip home. On the return journey, Lewis and Clark encountered multiple traders on the river who told them they’d been given up for dead.

On the morning of September 23 — two years, four months, and ten days after they’d departed — the Corps of Discovery returned to St. Louis, where they were greeted with gunfire salutes and cheering crowds.

Through gunshots, Grizzly bear encounters, crossing the Rockies, freezing winters, food shortages, and a few hostile meetings with Native American tribes, the Corps and Lewis and Clark recorded more than 200 plants and animals new to science and noted around 72 Indian tribes throughout their trip. After the expedition, Clark’s maps were duplicated and mass produced to allow further discovery and American settlement of the vast landmass they helped to establish and explore.