 <unk> searching for the fabled Northwest Passage and large inland seas in North America continued to pass through this region . Fort <unk> was built by the French in 1721 on Lake <unk> to facilitate exploration . In the 17th century a lucrative trade developed between Native Americans who trapped animals near the Great Lakes and traders who shipped the animal furs to Europe . For two centuries this trade network was the prime economic driver in the area . A notable result of this trade network was the Métis people , a mixed @-@ race community descended from Native Americans and French traders , as well as other mixed @-@ race peoples . In particular during the latter 18th century numerous French and English traders in the Minnesota region purchased Sioux wives in order to establish kinship relationships with the Sioux so as to secure their supply of furs from the tribes . 
