Minneapolis, the largest city in Minnesota, is situated on both sides of the Mississippi River at the 45th parallel. It lies upriver and west of St. Paul. The territory that eventually became Minnesota was first visited by Father Louis Hennepin in 1680, from whose exploration the French based their claim of jurisdiction. The land remained under French control until 1762, when it passed to the Spanish. Spain returned it to France in 1801, whereupon Napoleon negotiated its sale to the United States as part of the Louisiana Purchase in 1803. In order to establish its presence in the area, the United States built Fort Snelling in 1819, on land acquired by Lieutenant Zebulon Pike from the Sioux Indians near the junction of the Mississippi and Minnesota rivers in 1805. The the fort reservation corresponded to most of present-day Minneapolis as well as much of St. Paul. On the east side of the river, the community of St. Anthony was platted in 1849. In 1852, President Millard Fillmore signed an act of Congress that reduced the Fort Snelling reservation, opening more territory to white settlement. The number of settlers on the west side of the river quickly grew and the new community took the name of Minneapolis, meaning city of waters. Minneapolis was incorporated as a city in 1867 and five years later absorbed St. Anthony as well. The lumber industry initially flourished in the area surrounding Minneapolis, but eventually the timber was exhausted and the loggers moved farther west. The flour milling industry was established early in the city's development and has remained a mainstay of the economy. Eager to utilize the water power inherent in the Falls of St. Anthony, commercial interests developed a large canal along First Street South to deliver water to the mills. Subsequent developments almost ruined the falls before the citizens of Minneapolis recognized the value of the falls and took steps to preserve them. The Minnesota Legislature incorporated the University of Minnesota in 1851. Its first classes were held in St. Anthony. A lack of students and the onset of the Civil War led to the university being closed in 1861. It was reopened in 1869 and gave degrees to its first two graduates in 1871. The university now operates twenty different colleges and serves more than 45,000 students.