AP World History: Modern Unit 7 ReviewGlobal Conflicts (1900-Present)

AP World Unit 7 covers the era of global conflict from 1900 to the present, centered on World War I, the interwar crisis, World War II, and the mass atrocities those conflicts produced. The single biggest idea is that the Western-dominated world order of 1900 tore itself apart through total war, and old land-based and maritime empires gave way to new states, new ideologies, and new international institutions. Unit 7 is worth 8-10% of the AP exam, and it leans heavily on the causation skill, asking you to weigh which causes of conflict mattered most.

What this unit covers

Old empires collapse and power shifts

• At the start of the 20th century, Western powers controlled the global political order. By century's end, both land-based and maritime empires had given way to new states.
• The Ottoman, Russian, and Qing empires all collapsed from a combination of internal weakness (corruption, failed reform, ethnic tension) and external pressure (war, foreign intervention, economic competition).
• Russia's collapse led to the 1917 communist revolution and eventually the Soviet Union, the first state built on Marxist ideology.
• States outside Europe also challenged the existing order. The Mexican Revolution overthrew the Porfirio Diaz dictatorship and produced land reform and a new constitution.

World War I as total war

• WWI's causes form the classic MAIN package. Militarism, a flawed alliance system, imperialist competition for resources and territory, and intense nationalism turned a regional Balkan crisis into a global war.
• WWI was the first total war. Governments mobilized entire societies, not just armies, using propaganda, art, media, and intensified nationalism to keep populations (in home countries and colonies) committed to the fight.
• New military technology (machine guns, poison gas, tanks, submarines, airplanes) produced casualties on a scale nobody had planned for, which is why trench warfare turned into a years-long stalemate.
• Colonial troops and resources from Asia and Africa fed the war effort, which matters later because it fueled anti-imperial expectations after the peace.

The interwar years: depression, intervention, and unresolved tensions

• After WWI and the Great Depression, governments everywhere took a more active role in their economies. The hands-off approach was over.
• Compare the responses. The Soviet Union ran the economy directly through Five Year Plans, with rapid industrialization and repressive policies like collectivization that devastated peasants. The US used the New Deal to intervene within a capitalist system. Italy and Germany built fascist corporatist economies. Brazil and Mexico had governments with strong popular support steering economic life.
• The peace settlement did not end imperialism. Former German colonies transferred to Britain and France as League of Nations mandates, and Japan expanded into Manchuria (Manchukuo) and promoted the Greater East Asia Co-Prosperity Sphere.
• Anti-imperial resistance grew at the same time, led by groups like the Indian National Congress and West African nationalist movements.

World War II and its causes

• WWII grew out of four linked causes. The Treaty of Versailles created an unsustainable peace, the Great Depression destabilized economies and politics, imperialist ambitions continued (especially Japan's), and fascist and totalitarian regimes rose to power, above all Nazi Germany under Adolf Hitler.
• WWII was also a total war, fought with the same mobilization playbook as WWI but more extreme. Propaganda, nationalism, and ideology (fascism and communism) mobilized all of a state's resources, and totalitarian states repressed basic freedoms and controlled daily life.
• New technologies again escalated the killing, ending with the atomic bombings of Hiroshima and Nagasaki in 1945.

Mass atrocities after 1900

• Extremist groups in power attempted the destruction of specific populations. The Nazi murder of about six million Jews in the Holocaust is the central case.
• The pattern repeats across the century. Know the illustrative examples of genocide and ethnic violence, including the Armenians in the Ottoman Empire during and after WWI, Cambodia under the Khmer Rouge in the late 1970s, and the Tutsi in Rwanda in 1994.
• The skill here is causation. What conditions (war, extremist ideology, dehumanizing propaganda, state power) make mass atrocities possible, and what are their consequences?

Unit 7, Global Conflicts (1900-Present) at a glance

Why Unit 7, Global Conflicts (1900-Present) matters in AP World

Unit 7 is where the course's long-running stories about empire, industrialization, and nationalism crash into each other. The forces you tracked across earlier periods produce two world wars, the collapse of the old order, and institutions like the United Nations that still shape geopolitics today.

• It is the course's main showcase for the causation skill. Almost every topic asks you to explain causes and consequences and to judge which causes were most significant.
• It develops the governance theme. Total war, the New Deal, Five Year Plans, and fascist economies all show states claiming vastly more power over citizens' lives.
• It shows technology as a double-edged theme. Advances in science and industry brought better medicine and communication and also machine guns, gas, and atomic bombs.
• It explains where the modern map comes from. Mandates, collapsed empires, and postwar settlements drew borders that drive regional tensions today.

How this unit connects across the course

• The empires that collapse here are the ones built earlier. The Ottoman, Russian, and Qing land-based empires from Unit 3 finally fall in Topic 7.1, so use their long-term weaknesses (failed reforms, internal rebellion) as the internal causes (Unit 3).
• Imperialism and nationalism from the industrial era are direct causes of WWI. Competition for colonies and resources, plus the nationalism unleashed by earlier revolutions, comes straight out of Units 5 and 6 (Units 5-6).
• The industrial technologies of Unit 6 explain total war. Mass production, railroads, and chemical industries are why WWI and WWII could mobilize and kill on such a scale (Unit 6).
• WWII's aftermath launches the next two units. The weakened European powers, US-Soviet rivalry, and anti-imperial movements like the Indian National Congress set up the Cold War and decolonization (Unit 8), and the postwar institutions and economies feed into globalization (Unit 9).

Timeline

• 1908-1912: The Young Turk revolution and ongoing decline signal the Ottoman Empire's collapse from internal and external pressures.
• 1910: The Mexican Revolution begins, overthrowing the Diaz regime and challenging the existing political and social order outside Europe.
• 1911-1912: The Qing dynasty falls, ending over two thousand years of imperial rule in China.
• 1914: The assassination of Archduke Franz Ferdinand triggers the alliance system, and WWI begins.
• 1915: The Armenian genocide unfolds in the Ottoman Empire during the war, an early case of state-directed mass atrocity.
• 1917: The Russian Revolution topples the tsar and brings the Bolsheviks to power, creating the world's first communist state.
• 1919: The Treaty of Versailles ends WWI, transfers German colonies as League of Nations mandates, and plants the resentments that help cause WWII.
• 1929: The stock market crash starts the Great Depression, pushing governments worldwide to intervene in their economies.
• 1931: Japan invades Manchuria and sets up Manchukuo, showing imperialism continued between the wars.
• 1939: Germany invades Poland and WWII begins in Europe.
• 1941-1945: The Holocaust, the Nazi murder of about six million Jews, becomes the century's defining mass atrocity.
• 1945: WWII ends with the atomic bombings of Hiroshima and Nagasaki, opening the nuclear age and setting up the Cold War world of Unit 8.

Key people and groups

• Adolf Hitler: Nazi Germany's leader whose aggressive militarism and expansionism were the most direct cause of WWII in Europe, and who directed the Holocaust.
• Joseph Stalin: Soviet leader who ran the economy through Five Year Plans and collectivization, with repressive policies that devastated the population.
• Vladimir Lenin: Bolshevik leader of the 1917 Russian Revolution who established the communist Soviet state.
• Benito Mussolini: Italian fascist leader whose corporatist economy and authoritarian model influenced interwar Europe.
• Franklin D. Roosevelt: US president whose New Deal showed government intervention in a capitalist economy during the Depression.
• Indian National Congress: The leading anti-imperial organization pressing for Indian self-rule between the wars.
• The Khmer Rouge: The Cambodian extremist regime responsible for mass atrocities in the late 1970s.
• Nazi Party: The fascist totalitarian regime that mobilized Germany for total war and carried out the Holocaust.
• Porfirio Diaz: The Mexican dictator whose long rule provoked the Mexican Revolution of 1910.

Unit 7, Global Conflicts (1900-Present) on the AP exam

Unit 7 carries 8-10% of the exam weight, and its content shows up in every question format. Multiple-choice questions usually attach to a stimulus, such as a propaganda poster, a wartime speech, an economic chart from the Depression, or a treaty excerpt, and ask you to interpret it in context. Short-answer questions often hand you a historian's argument about the causes of WWI or WWII and ask you to support or modify it with evidence.

This is the strongest unit in the course for causation essays. A long essay question might ask you to evaluate the most significant cause of global conflict in the period 1900-1945, which means ranking causes (alliances vs. nationalism vs. economic crisis vs. fascism), not just listing them. Comparison prompts are also common, especially comparing government responses to the Great Depression (Five Year Plans vs. New Deal vs. fascist corporatism) or comparing total-war mobilization in WWI and WWII. For the DBQ, practice reading propaganda and official documents for point of view and purpose, since wartime sources are almost never neutral.

Essential questions

• Why did the Western-dominated global order of 1900 collapse into two world wars within fifty years?
• How did total war change the relationship between governments and the people they governed?
• Why did governments respond so differently to the same global economic crisis after 1929?
• What conditions allow states to attempt the destruction of entire populations, and why did this recur across the 20th century?

Key terms to know

• Total war: A conflict in which a state mobilizes its entire society, economy, and colonies for the war effort, not just its military.
• Propaganda: Government-produced media, art, and messaging designed to mobilize populations and intensify nationalism during wartime.
• Alliance system: The web of pre-1914 defense agreements that escalated a regional Balkan conflict into a world war.
• Treaty of Versailles: The WWI peace settlement whose harsh terms on Germany proved unsustainable and helped cause WWII.
• League of Nations mandates: The system that transferred former German colonies to Britain and France after WWI, continuing imperialism under a new label.
• Five Year Plans: Stalin's program of state-directed industrialization in the Soviet Union, achieved through central control and repression.
• New Deal: The US government's intervention in the economy during the Great Depression while keeping a capitalist framework.
• Fascism: An extreme nationalist, authoritarian ideology, exemplified by Italy and Nazi Germany, that organized the economy through corporatism and glorified the state.
• Totalitarianism: A system in which the state controls nearly all aspects of public and private life, repressing basic freedoms.
• Manchukuo: Japan's puppet state in Manchuria, evidence that imperial expansion continued between the world wars.
• Greater East Asia Co-Prosperity Sphere: Japan's framing of its empire in Asia as liberation, while actually extending imperial control.
• Holocaust: The Nazi state's systematic murder of about six million Jews during WWII, the central example of genocide in this unit.
• Genocide: The attempted destruction of a specific population, with cases including the Armenians, Cambodia under the Khmer Rouge, and the Tutsi in Rwanda.

Common mix-ups

• WWI's causes and WWII's causes overlap but are not the same. WWI is about alliances, militarism, imperialism, and nationalism; WWII adds the failed Versailles peace, the Great Depression, and the rise of fascism. An essay that treats them identically will lose analysis points.
• The interwar period is not a return to laissez-faire. Across capitalist, communist, and fascist states alike, the trend was more government intervention in the economy, just through different mechanisms.
• Imperialism did not end with WWI. The mandate system and Japanese expansion show empires holding on or growing between the wars; large-scale decolonization happens after WWII, in Unit 8.
• The Holocaust is the central case of mass atrocity, but the topic spans the whole century. Be ready to discuss the Armenian genocide, Cambodia, and Rwanda as part of the same pattern of extremists in power targeting populations.