Have students work in groups or as a class and facilitate a discussion about some of the positive and negative effects that European and American exploration had on Native Americans, Europeans, and Americans. While historians often write of the conflict on the northern Great Plains between Native American nations, Europeans, and Americans there were also encounters that led to positive cultural and material exchange. The first contact between Native Americans, Europeans, and Americans often came when European and American men explored the region searching for a transportation route over the continent and the potential for trade—especially in furs. By 1700, northern Plains peoples knew of European presence in North America. Iron and other metals began to affect the way Native Americans made arrowheads and stored and cooked their food. Missionaries began to bring new ideas about religion to tribes all over the continent. Horses may have had the greatest impact changing the way people traveled, carried their possessions, and hunted. How do they know? What is their knowledge based on?