Bridge in the Bitterroot Mountains range of the Rocky Mountains in western Montana.

Black and white photograph of a Mississippi River bridge at Winona, Minnesota. Water damage is visible on the image, which was scanned from the negative.

Black and white photograph of a Mississippi River bridge at Dubuque, Iowa. Water damage is visible on the image, which was scanned from the negative.

Black and white photograph of a wooden covered bridge at Fox Creek. Taken by Robert Merrill on a trip to Middleburgh, New York. A car can be seen at the bridge opening.

Black and white photograph of two people standing on a wood bridge at Fox Creek. Taken by Robert Merrill on a trip to Middleburgh, New York.

The Blue Water cantilever bridge connects Port Huron, Michigan and Sarnia, Ontario.

The Blue Water cantilever bridge connects Port Huron, Michigan and Sarnia, Ontario.

Black and white lantern slide of the Tasquillo bridge.

Black and white photograph of a metal bridge. People are visible walking along the side of the bridge, and automobiles are driving in the middle of the bridge.

Black and white photograph of A man on a boat overlooking a town next to a wooden bridge. Automobiles and people walking fill the bridge and the street leading to the bridge.

Black and white photograph of a cement bridge over a rocky river. The image is taken from river level, and a man is visible standing among the boulders of the river. Two people can be seen standing on the bridge.

Black and white lantern slide of the Cabin John Bridge, also known as the Union Arch Bridge, in Cabin John, Maryland.