Captain Meriwether Lewis (1774-1809)

Meriwether Lewis, with co-captain William Clark, led an 8,000-mile expedition to the West coast and back from 1804 to 1806. Known as the "Corps of Discovery," the expedition's mission was to find a water passage to the Pacific Ocean. The explorers discovered 178 new plants and 122 species and subspecies of animals. Their journals and maps opened the door for America's westward expansion.

Credit: Independence National Historical Park

Captain William Clark (1770-1838)

William Clark served with Meriwether Lewis as co-captain of the Corps of Discovery from 1804 to 1806. The 28-month expedition explored western lands never before seen by Americans. Clark had many skills, including being an excellent boatman—particularly important because more than 80 percent of the trip was by water. He also was a natural and gifted cartographer, or map maker.

Credit: Independence National Historical Park