AP World - Period 6 Review (1900 C.E. to Present)

Overview

AP World Period 6 covers c. 1900 to the present, the final stretch of AP World History: Modern, and it spans Unit 7 (Global Conflict), Unit 8 (Cold War and Decolonization), and Unit 9 (Globalization). Each of these units is weighted at 8-10% of the exam, so the 1900-to-present era carries roughly 24-30% of your score. That makes it one of the highest-payoff chunks of the course to review.

The big story of the period is the collapse of the old imperial order and the construction of something new. The century opens with the West dominating global politics and closes with decolonized nation-states, international institutions like the United Nations, and a globally integrated economy. Three throughlines tie the units together: empires give way to new states, the state's role in the economy keeps shifting, and rapid science and technology change everything from warfare to medicine. One note on dates: events and processes are not locked inside unit boundaries, so developments often begin before or continue after the approximate dates assigned to each unit.

You won't be asked to recall an exact date in isolation, but you do need rough chronology so you can sequence causes and effects. Anchor your review around these:

Unit 7: Global Conflict (c. 1900-Present)

Unit 7 explains how the world fought two total wars in thirty years. The core argument: imperial competition, nationalism, economic crisis, and extremist ideologies turned regional tensions into global catastrophe.

Shifting power after 1900

The 20th century opens with the West dominating the global political order, but the old land-based empires were already cracking. The Ottoman, Russian, and Qing empires all collapsed from a mix of internal and external pressures. Russia's collapse mattered most for the rest of the century because it produced a communist revolution in 1917. Meanwhile, states like Mexico challenged the existing order through revolution born of political crisis (the Mexican Revolution, 1910-1920). Hold onto this pattern, because "peoples and states challenge the existing order" is the shared thread connecting Units 7 and 8.

Causes and conduct of World War I

World War I (1914-1918) grew from imperialist expansion and competition for resources, territorial and regional conflicts, a flawed alliance system, and intense nationalism. The assassination of Archduke Franz Ferdinand by a Serbian nationalist in 1914 triggered the alliance commitments that escalated a Balkan crisis into a global war.

WWI was the first total war. Governments mobilized their home populations and their colonial populations using political propaganda, art, media, and intensified nationalism, while new military technology (machine guns, tanks, chemical weapons, trench warfare) drove casualties to unprecedented levels. The mobilization of colonized peoples is a favorite exam angle, so know examples like Indian soldiers fighting for Britain and West African troops fighting for France.

The interwar period: economic crisis and unresolved tensions

After WWI and the onset of the Great Depression (1929), governments took a much more active role in economic life. Know the different models: the Soviet Union controlled its economy through the Five Year Plans backed by repressive policies, the United States responded with the New Deal, Italy and Germany built fascist corporatist economies, and popularly supported governments in Brazil and Mexico intervened in their own ways. This is a classic comparison setup and a key piece of the course's Economic Systems theme.

Politically, the interwar peace solved little. Western and Japanese imperial states mostly kept their colonies, and some gained territory through League of Nations mandates (former German colonies went to Britain and France) or outright conquest (Japan's Manchukuo and the Greater East Asia Co-Prosperity Sphere). Anti-imperial resistance grew anyway, through the Indian National Congress and West African strikes and congresses against French rule.

World War II: causes and conduct

WWII's causes stack up directly from WWI: an unsustainable peace settlement (the Treaty of Versailles imposed reparations and territorial losses on Germany), the global economic crisis of the Great Depression, continued imperialist aspirations, and above all the rise of fascist and totalitarian regimes, culminating in Nazi Germany's aggressive militarism under Adolf Hitler.

WWII was also a total war, and the exam loves the comparison with WWI. Governments on both sides, democracies under Churchill and Roosevelt and totalitarian states under Hitler and Stalin, used propaganda, nationalism, and ideologies (fascism, communism) to mobilize all available resources, with totalitarian states repressing basic freedoms in the process. New technology and tactics, including fire-bombing and the atomic bomb, pushed casualties even higher. When you see "explain similarities and differences in how governments conducted war," this WWI-vs-WWII parallel is the intended answer.

Mass atrocities after 1900

Extremist groups in power attempted to destroy specific populations. The Nazi killing of the Jews in the Holocaust is the central case, alongside the Armenian genocide in the Ottoman Empire, Cambodia under the Khmer Rouge, the genocide of the Tutsi in Rwanda, and the Holodomor in Soviet Ukraine. Unit 7 closes with a causation capstone: weighing the relative significance of the causes of global conflict, which is a ready-made LEQ frame.

Unit 8: Cold War and Decolonization (c. 1900-Present)

Unit 8 covers two overlapping stories happening at once after WWII: the superpower standoff between the US and USSR, and the dissolution of European empires. They constantly intersect, because newly independent states became the battlegrounds of the ideological struggle.

Setting the stage and the superpower rivalry

Hopes for self-government went largely unfulfilled after WWI, but after WWII rising anti-imperialist sentiment drove the dissolution of empires, while the victors' technological and economic gains shifted the global balance of power. Out of that shift came the Cold War: the democratic, capitalist United States and the authoritarian, communist Soviet Union emerged as superpowers locked in an ideological struggle between capitalism and communism. Not everyone picked a side. The Non-Aligned Movement, with leaders like Sukarno in Indonesia and Kwame Nkrumah in Ghana, promoted alternatives to choosing a bloc.

Effects of the Cold War: alliances, nukes, and proxy wars

The Cold War produced new military alliances (NATO and the Warsaw Pact), nuclear proliferation, and proxy wars fought between and within postcolonial states in Latin America, Africa, and Asia. Know three by name: the Korean War (1950-1953), the Angolan Civil War, and the Sandinista-Contras conflict in Nicaragua. The takeaway is that the superpowers rarely fought each other directly; the violence landed on the postcolonial world.

The spread of communism

In China, internal tension and Japanese aggression enabled the communists to seize power in 1949, and communist China then controlled its economy through the Great Leap Forward with repressive policies. Beyond China, movements to redistribute land and resources arose across Africa, Asia, and Latin America: the Vietnamese independence revolution, Mengistu Haile Mariam in Ethiopia, land reform in Kerala, and the White Revolution in Iran. Trace the full communist arc across the period: Russian Revolution, Five Year Plans, Cold War ideological struggle, Chinese revolution, Soviet collapse.

Decolonization and newly independent states

Nationalist leaders and parties, including the Indian National Congress, Ho Chi Minh, Nkrumah, and Nasser, sought autonomy or full independence. The exam's favorite distinction: some colonies negotiated independence (India, the Gold Coast, French West Africa) while others fought for it (Algeria, Angola, Vietnam). Regional, religious, and ethnic movements like the Muslim League, Quebecois separatism, and the Biafra secession also challenged colonial rule and the borders it left behind.

Redrawn boundaries created new states (Israel, Cambodia, Pakistan) and caused conflict and massive population displacement, especially the Partition of India in 1947 and the creation of Israel in 1948. New governments often guided economic life to promote development, as with Nasser's Egypt, Indira Gandhi's India, Nyerere's Tanzania, and Bandaranaike's Sri Lanka. Meanwhile, migration to former imperial metropoles (South Asians to Britain, Algerians to France, Filipinos to the United States) maintained colony-metropole ties after empire ended, a bridge straight into Unit 9's globalized world. These political transformations are the heart of the Governance theme in this period.

Resistance to the established order

People challenged the century's conflicts and power structures in very different ways. Gandhi, Martin Luther King Jr., and Nelson Mandela promoted nonviolence as a route to political change. Militarized states like Pinochet's Chile, Franco's Spain, and Idi Amin's Uganda, along with the military-industrial complex, intensified conflict instead. And some movements, including the Shining Path and Al-Qaeda, used violence against civilians to pursue political aims. A strong essay distinguishes among these methods rather than lumping all "resistance" together.

The end of the Cold War

Three forces ended the Cold War: advances in US military and technological development, the Soviet Union's costly failed invasion of Afghanistan, and public discontent plus economic weakness inside communist countries. The Berlin Wall fell in 1989 and the Soviet Union collapsed in 1991. Unit 8's capstone asks how similar the Cold War's effects were in the Eastern and Western Hemispheres, another prebuilt LEQ frame worth outlining in advance.

Unit 9: Globalization (c. 1900-Present)

Unit 9 zooms out from wars and politics to the technologies, economies, cultures, and institutions that tied the world together, plus the pushback against that integration.

Technology, medicine, and the environment

New communication technologies (radio, cellular, the internet) and transportation technologies (air travel, shipping containers) shrank geographic distance. Petroleum and nuclear power raised productivity. The Green Revolution sustained a growing global population, vaccines and antibiotics extended human life, and birth control transformed reproductive practices and lowered fertility rates. This is the Technology and Innovation theme at full speed.

But technology had limits. Diseases of poverty like malaria, tuberculosis, and cholera persisted, new epidemics emerged (the 1918 influenza pandemic, Ebola, HIV/AIDS), and increased longevity raised rates of heart disease and Alzheimer's. On the environmental side, human activity drove deforestation, desertification, declining air quality, and freshwater depletion, intensifying competition for resources, while greenhouse-gas emissions fueled debates about the nature and causes of climate change.

Economics in the global age

Accelerated by the Cold War's end, governments turned toward free-market policies and economic liberalization under Reagan in the US, Thatcher in Britain, Deng Xiaoping in China, and Pinochet in Chile. Notice the reversal: the interwar and postwar decades were the age of state intervention (Five Year Plans, New Deal, state-guided development), and the late century swung back toward markets. Knowledge economies grew in places like Finland, Japan, and the US while manufacturing shifted to Asia and Latin America (Vietnam, Bangladesh, Mexico, Honduras). Multinational corporations like Nestle, Nissan, and Mahindra and Mahindra, plus trade institutions like the WTO, NAFTA, and ASEAN, spread free-market practice worldwide.

Calls for reform and expanding rights

Rights-based discourses challenged old assumptions about race, class, gender, and religion: the UN Universal Declaration of Human Rights, global feminism, Negritude, and liberation theology. Access to education and political and professional roles became more inclusive, from women's suffrage (the US in 1920 through Morocco in 1963) to the US Civil Rights Act of 1965, the end of apartheid, and caste reservation in India. Movements like Greenpeace, the Green Belt Movement, and the World Fair Trade Organization protested the unequal environmental and economic consequences of global integration. These shifts in hierarchy and identity sit at the core of the Social Interactions and Organization theme.

Global culture, resistance, and institutions

In the second half of the century, popular and consumer culture went global: reggae, hip-hop, and K-pop; Bollywood and Hollywood; BBC and CNN; World Cup soccer and the Olympics; Facebook, Twitter, and Instagram; Alibaba, eBay, and Amazon; Toyota, Coca-Cola, and McDonald's. Resistance to globalization took many forms too, including anti-IMF and anti-World Bank activism and locally developed alternatives like Weibo in China. And new international organizations, most importantly the United Nations, formed with the stated goal of maintaining world peace and facilitating international cooperation. Unit 9's capstone asks the extent to which science and technology brought change from 1900 to the present, the period's continuity-and-change LEQ frame.

Key Concepts and Vocabulary

These terms carry the most weight in Units 7-9. For the full course glossary, check the AP World key terms page.

• Total war is warfare that mobilizes entire societies, home and colonial populations included, through propaganda, media, and nationalism. Both world wars qualify.
• Fascism and totalitarianism are the extremist ideologies behind WWII's outbreak, exemplified by Nazi Germany under Hitler.
• Great Depression refers to the global economic crisis beginning in 1929 that pushed governments into more active economic roles.
• Five Year Plans were the Soviet Union's system of state economic control, enforced with repressive policies.
• New Deal was the US response to the Depression, an example of government intervention within a democracy.
• Holocaust was the Nazi killing of the Jews, the central case of 20th-century genocide alongside the Armenian genocide, Cambodia, Rwanda, and the Holodomor.
• League of Nations mandates transferred former German colonies to Britain and France after WWI, showing empire's persistence between the wars.
• Superpowers were the United States and Soviet Union, rivals in the Cold War's ideological struggle between capitalism and communism.
• NATO and the Warsaw Pact were the opposing Cold War military alliances.
• Proxy wars were Cold War conflicts fought through postcolonial states, like the Korean War, the Angolan Civil War, and the Sandinista-Contras conflict.
• Non-Aligned Movement was the bloc of states, led by figures like Sukarno and Nkrumah, that refused to side with either superpower.
• Decolonization is the dissolution of empires after WWII, through negotiation (India, the Gold Coast) or armed struggle (Algeria, Vietnam).
• Partition of India (1947) split British India into India and Pakistan, causing mass displacement and violence.
• Great Leap Forward was communist China's repressive program of state economic control under Mao.
• Nonviolence was the strategy of political change promoted by Gandhi, Martin Luther King Jr., and Nelson Mandela.
• Economic liberalization is the late-century turn toward free-market policies under Reagan, Thatcher, Deng Xiaoping, and Pinochet.
• Green Revolution refers to agricultural innovations that sustained a rapidly growing global population.
• Multinational corporations like Nestle and Nissan spread free-market practices across borders, alongside institutions like the WTO, NAFTA, and ASEAN.
• Universal Declaration of Human Rights is the UN document anchoring the period's rights-based challenges to old hierarchies.
• United Nations is the international organization formed to maintain world peace and facilitate cooperation.

How This Period Shows Up on the Exam

Units 7-9 together account for roughly 24-30% of the AP World exam, and this content can appear on every question type. SAQs 1 and 2 (the stimulus-based ones) can draw from 1200-2001, SAQ 4 (no stimulus, choose-one) focuses on 1750-2001, the DBQ comes from 1450-2001, and the third LEQ option focuses primarily on 1750-2001. Translation: modern content is fair game almost everywhere, but the course's own coverage effectively runs through 2001, so prioritize developments up to that point.

The College Board's released sample DBQ sits squarely in this period: "Evaluate the extent to which the experience of the First World War changed relationships between Europeans and colonized peoples," using documents like intercepted Indian soldiers' letters, a French colonial postcard, a 1919 Egyptian protest song, and African veterans' petitions and oral histories. Released sample multiple-choice questions include paired Dow Chemical (1972) and NCR (1989) passages testing economic liberalization, offshoring of manufacturing, and antiglobalization activism, which is exactly the Unit 9 material above.

Each unit's capstone topic is a prebuilt essay frame, so practice outlining all three: the relative significance of the causes of global conflict (Unit 7), the extent to which the Cold War's effects were similar across hemispheres (Unit 8), and the extent to which science and technology brought change from 1900 to the present (Unit 9). Older released essays from this era also make solid practice, including prompts on the Green Revolution, comparing the Mexican, Chinese, and Russian revolutions, and the effects of WWI. Just note that the current exam's DBQ uses seven documents and the rubrics differ from older versions, so use past exam questions for content practice and current rubrics for scoring.

Practice and Next Steps

Start by self-testing the period's three big arcs: empires to new states, state intervention to liberalization, and technology's double-edged effects. If you can narrate each arc with specific evidence from all three units, you're in good shape for any causation or continuity-and-change prompt.

Then put it under exam conditions. Run stimulus-based questions on this era with guided MCQ practice, write a timed DBQ or LEQ with FRQ practice and instant scoring, and when you're ready to see how Units 7-9 fit into the whole course, take a full-length practice exam. After scoring yourself, the AP score calculator shows where your performance lands on the 1-5 scale.