Who was Lewis and Clark?

Lewis and Clark, led an expedition to survey the land West of the Mississippi, request of President Thomas Jefferson. The land that they were exploring was known as Louisiana Territory, that had been purchased from France in 1803. Lewis, Clark and the rest of their expedition began their journey near St. Louis, Missouri, in May 1804. This group-often called the Corps of Discovery by historians-faced nearly every obstacle and hardship imaginable on their trip.