St. Lawrence Seaway Western Terminus, New York

Cape Vincent marks the interior end of the St. Lawrence Seaway, a network of canals and locks adjacent to the St. Lawrence River, built between 1954 and 1959, that made it possible for large commercial ships to travel from the interior of the continent (the Great Lakes) to the Atlantic Ocean. It connects Montreal, Quebec, with Lake Ontario and, at 189 miles, is the longest artificial seaway in the world. Ships soon outgrew the seaway (just as the Erie Canal, which the seaway replaced, was outgrown), and it now sees only a fraction of its earlier traffic.