Black and white lantern slide of a breakwater structure near a canal lock at Wei Hu, China.

Black and white photograph of the steamer Medora at the Port Carling Lock, Ontario. Several people are visible on the boat deck and the ground below.

Black and white photograph of the steamer Sagamo at the Port Carling Lock, Ontario. Several people appear to be boarding the vessel.

Black and white photograph of the Poe Lock, Sault Ste. Marie, Michigan. A boat is visible in the background.

Black and white lantern slide of St. Peter's Lock on Bras d'Or Lake, Nova Scotia.

Black and white photograph of a lock. A building is next to the lock, and a flagpole and flag are visible in the center of the image. Taken my Merrill while attending the American Society of Civil Engineers conference in New Orleans, Louisiana.

Locks at Sault Sainte Marie, Michigan.

Locks at Sault Sainte Marie, Michigan.

Imperoyal Sarnia going through the locks at Sault Ste. Marie.

Black and white photograph of a partially frozen river in the middle of a city. Buildings are visible on both sides of the river, and there is a bridge across the river in the distance.

Black and white photograph of a person standing on a hill of mining spoil in front of several buildings and a smokestack in Little Falls, New York.

Black and white photograph of a hydraulic lock in Little Falls, New York.