James Monroe's $15 million purchase of the Lousiana Territory in 1803 gave America 830,000 square miles of unchartered land west of the Mississippi. What was contained in this vast area was contained in this vast area was anyone's guess. The call for exploration was answered by brave adventurers pathfinders and mountain men who led the way to a new America. Vintage maps and detailed accounts help define their trailblazing glory. Travel to uncharted territory on Lewis and Clark's pioneering trek to the Pacific; the Rocky Mountain travels of John Charles Fremont and mapmaker Carl Preuss; the first-known voyage down the Colorado River by early environmentalist John Wesley Powell and much more.