Hand to hand combat along a trench at Ypres in 1914. (OSA, Oregon State Defense Council Records, World War I Photographs)

American soldiers use picks and shovels to work on a trench near St. Mihiels. (OSA, Oregon State Defense Council Records, World War I Photographs)

French soldiers move along one of a network of trenches on their way to fight at the front lines. (OSA, Oregon State Defense Council Records, World War I Photographs)

An aerial view of a battlefield shows a German trench line being overrun late in the war. The pock marks are huge craters left by artillery shells. (OSA, Oregon State Defense Council Records, World War I Photographs)