Unit 7: Global Conflict (1900–Present)
AP World History: 55 practice questions with detailed explanations.
Unit Study Guide
Executive Summary
The twentieth century's first half was consumed by total war: two world wars, the collapse of empires, economic depression, and mass atrocities on an industrial scale.
World War I (1914–18)
Alliances, militarism, imperialism, and nationalism — plus the assassination at Sarajevo — ignited a war that mobilized entire societies (total war). Trenches, poison gas, and machine guns produced slaughter. The Treaty of Versailles punished Germany; the Ottoman, Austro-Hungarian, Russian, and German empires collapsed.
The interwar period
The 1918 flu pandemic killed more than the war. The Russian Revolution (1917) produced the first communist state. The Great Depression (1929) discredited liberal economics and fueled fascism in Italy and Nazism in Germany. Japan invaded Manchuria (1931) — Asia's war began early.
World War II (1939–45)
Axis aggression met Allied resistance. Germany's blitzkrieg, the Holocaust (systematic murder of six million Jews), Japan's Pacific empire, the Allied bombing of cities — and finally the atomic bombs on Hiroshima and Nagasaki (1945). The war ended with 60+ million dead.
Mass atrocities
The Holocaust; the Armenian genocide (1915); the Nanking Massacre (1937); the Bengal famine — the century industrialized killing. Genocide became a named crime at Nuremberg (1945).
Exam traps
WWII began in Asia (1937) and Europe (1939) — don't date it only to Pearl Harbor. Total war means civilian economies and populations were targets. The Treaty of Versailles' harshness fed German resentment, but was not the sole cause of WWII. The Holocaust was systematic and industrialized — a state project, not spontaneous violence.