The battlefields of World War I brought the concept of trench warfare to a new extreme. The war, which drastically changed the world, saw the weaving, snake-like pathways crop up quickly and over long distances.
Those trenches, and the mine-filled and crossfire-laden No Man's Land between them, comprised some of the most gruesome living conditions from any war. That's what makes these aerial photos of World War I battlefields - many from the book The Great War Seen From the Air - both horrifying and remarkable.
Soldiers fought the Battle of Soissons over a four-day period, from July 18 to July 22 in 1918. It was waged between the French - who had American assistance - and the Germans.
Formed during the Battle of the Somme, the Lochnagar Crater appeared when a mine exploded under the German front lines.