an expedition that started E pluribus unum

Just watched 2-hour "Lewis & Clark" in PBS. In 1803, after Thomas Jefferson bought Louisiana from France, he sent a 30-person team headed by Lewis and Clark in a arduous and trail-blazing expedition into an uncharted territory from St. Louis all the way to Pacific coast. This heroic expedition inspired many adventurous Americans and, driven by the mindset of Manifest Destiny, started the rapid territorial expansion westward. Finally, an E pluribus unum of the United States was formed.