Clark had high praise for the American Indians' canoes, such as this one sketched on Feb. 1, 1806. "I have Seen the nativs near the Coast rideing waves in these Canoes in Safty and appearantly without Concern when I Should it impossible for any vessel of the Same Size to have lived or kept above water a minute," he wrote.
Lewis and Clark braved the unknown waters of the Missouri to chart America's future. As we approach the 200th anniversary of their sojourn, TIME reflects upon their sacrifice and achievement