Jay Cooke is noted for its Rustic Style historical structures. These structures were built by the Civilian Conservation Corps between 1933 and 1942. All the major landmarks in Jay Cooke are built with local basalt or gabbro stone and dark planks and logs. Most famous of all landmarks is the swinging bridge, which is one of only two suspension bridges in any Minnesota state park. The bridge was designed by Oscar Newstrom. It runs long, of which run over the river itself. It is supported by two large concrete pylons also faced with gabbro. The bank of the river near the River Inn is too steep to walk along, so anyone who wishes to hike the length of the river generally must cross this bridge. In the major floods of June 20, 2012, the swinging bridge was severely damaged. According to an early report from the Pine Journal, at least one stone pillar and half of another were washed away, and the bridge decking was "twisted and mangled." The CCC structures are grouped into three historic districts which are separately listed on the National Register of Historic Places. These districts are the Rustic Style District, including the River Inn and Swinging Bridge; the Rustic Style Picnic Grounds, including the shelter, water tower and latrine, and drinking fountain; and the Rustic Style Service Yard, including the custodian's cabin and pump house. Early canoe route Minnesota geography is dominated by three major watersheds which carry the surface waters of the state north to Hudson Bay, east to the Great Lakes, and south into the Mississippi River. The rivers, creeks, and associated lakes within these drainage basins essentially describe the route geography of the thoroughfares used by American Indians for centuries, and later by European explorers, missionaries, and fur traders. But water travel was subject to interruption caused by rapids, falls, or shallows, and not all of the major lakes and rivers were interconnected, making it necessary to portage from time to time. The earliest North American fur trading did not include long-distance transportation of the furs after they were obtained by trade with the Indians; it started with trading near settlements or along the coast or waterways accessible by ship. But later, Coureur des bois achieved business advantages by traveling deeper into the wilderness and trading there. By 1681, the French authorities decided to control the traders. Also, as the trading process