"Your woman who accompanied you that long dangerous and fatigueing rout to the Pacific Ocian and back diserved a greater reward for her attention and services on that rout than we had in our power to give her at the Mandans." - William Clark in a letter to Sacagawea's husband

"Ocian in view! O! The Joy!" - William Clark, journal entry dated November 7, 1805

It is the most fabled and storied journey in American history. From 1804-1806, the first expedition across the North American continent was commissioned by President Thomas Jefferson, who had recently bought a vast swath of territory from France. Though he knew he had bought a huge amount of land, Jefferson wasn't entirely sure of what he had bought, so he asked a team led by Meriwether Lewis and William Clark to traverse the continent until they reached the Pacific, studying everything from the ecology to geography along the way to get an understanding of the country's new region.

Lewis and Clark would find far more than they bargained for. The 33 members who made the trip came into contact with about two dozen Native American tribes, many of whom helped the men survive the journey. Though they suffered deaths on their way west, the group ultimately reached the Pacific coast and got back to St. Louis in 1806, having drawn up nearly 150 maps and giving America a good idea of much of what lay west.