World War I in photos of soldiers and civilians

World War II: After the War. Part 20 of a weekly 20-part retrospective of the war. Part 20 is a weekly retrospective of WWII. Part 21 is a look at the aftermath of the conflict. Part 22 is the first part of the 20th part of this week's 20th series of World War I.

Animals were used in World War I on a scale never before seen. Horses were used as cavalry mounts and beasts of burden. Mules, dogs, camels, and pigeons all played vital roles in the war. All at great risk, and with heavy cost.

In 1914, the German Army sought a swift decisive victory over France, invading from the north. The plan failed, leading to a years-long bloody stalemate where millions of soldiers fought for mere yards of territory. Millions of soldiers braved horrific conditions fighting for mere inches of territory on the Western Front.

As countries caught up in the war sent soldiers to the front lines, they also built support behind the lines and at home, with women taking many roles. As villages became battlefields, refugees were scattered across Europe.