Open University
Ferdinand's murder sent the Great Powers into a war that would last five years and cost the lives of 10 million troops.
Thought of as the "war to end all wars," World War I marked a number of firsts in military conflict, including the use of planes, tanks, and chemical weapons.
On June 28, 1919, the victorious Allied leaders signed the Treaty of Versailles, officially ending World War I and spurring German nationalism, which in turn gave Nazi leader Adolf Hitler a political platform.
Here's a few colorized photographs published by The Open University showing life during World War I.