(cover story)

The waiting room at St. Lambert Lock in Montreal looks out at a quarter-mile of chain-link fence, six security camera towers, a blaze-orange derrick and a guardhouse. There, three armed men stare at a 750-foot stretch of placid, blue-green water waiting to lift 33,000-ton freighters up along the St. Lawrence Seaway.

The lock is part of the oldest and most traveled inland waterway in America — a 2,300-mile corridor that connects the Atlantic Ocean with all five Great Lakes and the Mississippi River. Since deep draft navigation opened on the St. Lawrence in 1959, more than two and a half billion tons of cargo, worth around $375 billion, have traversed the seaway.