Great Lakes nations maintain coast guard vessels in the Great Lakes. During settlement, the Great Lakes and its rivers were the only practical means of moving people and freight. Barges from middle North America were able to reach the Atlantic Ocean from the Great Lakes when the Welland canal opened in 1824 and the later Erie Canal opened in 1825. By 1848, with the opening of the Illinois and Michigan Canal at Chicago, direct access to the Mississippi River was possible from the lakes. With these two canals an all-inland water route was provided between New York City and New Orleans. The
Griebnitzsee of lakes towards the Großer Wannsee. The remaining water flows through the Griebnitzsee to its western end, where it flows into the River Havel near Potsdam. The length of the Griebnitzsee is navigable, and forms part of the Teltow Canal route that links the River Havel with the River Spree and the Oder-Spree Canal, bypassing the reach of the River Spree through central Berlin. The navigable Griebnitz Canal provides an alternative link from the Griebnitzsee to the River Havel via the Großer Wannsee. During the time of the Berlin Wall, the border between Berlin and East Germany ran down the