People have lived in the area now called North Dakota for over 12,000 years. The people of prehistoric times were nomadic hunters and gatherers. More recent Native American tribes of this area include the Mandan, Arikara and Hidatsa. These Plains Village people lived in earthlodges in permanent villages. Many of these villages were located along the Missouri River. They raised crops such as corn, beans, squash, sunflowers and tobacco. A trade network extended as far as the Gulf of Mexico and the Pacific Ocean. They also hunted big game, especially the buffalo. With the arrival of European people in the 1700's, the culture of the Native Americans changed. The introduction of European diseases, the destruction of the buffalo herds, and the steady encroachment of settlers made it impossible for these Native American peoples to retain their traditional way of life. Meriwether Lewis and Capt. William Clark set out to explore the newly purchased Louisiana Territory on May 14, 1804. They were to record the course of the Missouri River to its headwaters and look for a direct water route across the continent. The party consisted of 44 unmarried young men who were, in Capt. Lewis' words, "capable of bearing bodily fatigue in a pretty considerable degree." In late October of 1804 the expedition reached the Knife River Indian villages and built Ft. Mandan as their winter camp. It was there that Lewis and Clark hired Toussaint Charbonneau and his young Shoshoni wife, Sakakawea. Fort Stevenson was a two company military post named for Union General Thomas G. Stevenson. Construction of the fort began in 1867. It was built at the mouth of Garrison Creek. The fort served four main purposes: to protect the Three Tribes at Fort Berthold; to serve as a link in the chain of military forts from South Dakota to Montana; as a point in the proposed emigrant route from Minnesota to the gold mines; and as a base of supplies for Fort Totten. Fort Stevenson was built for a maximum of 238 men. No major attacks were ever made on Fort Stevenson and by 1894 Fort Stevenson was dissolved. The site of the fort has been inundated by the waters of Lake Sakakawea. The Totten Trail was a wagon trail connecting Fort Stevenson, located at the mouth of Garrison Creek, and Fort Totten, a military post on Devils Lake. Both forts were built in 1867 and the 125 mile trail between them was in constant use until 1872. The trail served as a mail and a supply route. A portion of the trail near the Dog Den Range became known as the land of strange disappearances when several mail carrying parties were attacked and killed. The trail's importance diminished after 1872 as the railroads provided cheaper and faster routes for mail.