Wherever one is in Montana, one stands in the pathway of Lewis and Clark, whose 1804-1806 expedition set out to investigate the people and resources of the newly acquired Louisiana Purchase and to seek a navigable passage across the Rocky Mountains to the Pacific. Like earlier French and Spanish voyages across North America, the Corps of Discovery brought back information that changed life in this land forever. In the 19th century, North America was in turmoil as Indian nations, recovering from five waves of smallpox, pushed west while Europeans raced to conquer more territories. Although others had explored, traded, and trapped in the Northern Plains, Lewis and Clark were the first to come for military, scientific, and economic development reasons, and their expedition defined agendas and relationships between cultures and between people and the land that people of the West are still sorting out. The Corps of Discovery included Indians, French, Euro-Americans, men of mixed European and Indian decent, one black, a woman, and a baby, and Indian people of many nations fed, guided, and helped the Corps with few violent altercations. In what is now Montana, the expedition explored 1,900 miles of wilderness, catalogued 63 species of plants and animals new to science, and charted significant geographic features, including seven National Historic Landmarks and Monuments: Pompeys Pillar, the Great Falls Portage, the Three Forks of the Missouri, Lemhi Pass, Lolo Pass, Traveller's Rest, and the Upper Missouri Breaks. Montana remains a land of many cultures where some landscapes, wildlife, and native plants can still be seen much as the Corps recorded them, alongside evidence of the cultural cooperation, conflicts, and collisions in values that have defined the West for two centuries.