The war that ended the old world.
Causes, course, and end of the first total industrial war. From the assassination at Sarajevo through the Treaty of Versailles, with the empires that fell along the way.
World War I (1914–1918) ended the long 19th century. A Balkan assassination triggered alliance commitments that pulled in every major European power within weeks. The war that everyone expected to be over by Christmas became four years of industrial slaughter on the Western Front, where machine guns and barbed wire made offense impossible. Russia collapsed in 1917 (Bolshevik Revolution); the U.S. entered the same year and tipped the balance. The Treaty of Versailles (1919) imposed punitive terms on Germany, dismantled the Ottoman, Austro-Hungarian, and Russian empires, and built the unstable interwar order — including the failed League of Nations.
The story, topic by topic.
- 1.
Long-term causes
Militarism, alliances, imperialism, nationalism — the powder keg. - 2.
July Crisis 1914
Sarajevo to general mobilization in five weeks. - 3.
The Western Front
Trench warfare. The Marne, Verdun, the Somme. Roughly a foot of ground per casualty. - 4.
A global war
Eastern Front, Italian Front, Mesopotamia, East Africa, the Pacific — and the colonies on every side. - 5.
Russia leaves
February and October Revolutions 1917; Brest-Litovsk 1918. - 6.
U.S. entry and the end
April 1917. The Hundred Days. November 11, 1918. - 7.
Versailles 1919
Punitive terms, redrawn maps, the League — and the seeds of the next war.
Where this shows up in your courses
APWH:Unit 7 covers WWI in global context.
APUSH:Period 7 covers U.S. entry.
Era page:The Modern World for broader context.
This era anchors 1 APWH unit
Studying for the AP exam? These units cover material that overlaps with this era — with CED-aligned topics, key terms, and exam focus tips for each.
