From the Iron Curtain and the Berlin Wall to decolonization, European integration, and the collapse of the Soviet Union — how the ideological standoff between East and West, the retreat from empire, and the long path toward unity reshaped Europe from 1945 to today.
Six ways to master Unit 9 — pick whichever fits how you like to study.
Seven topics from the College Board CED, in order.
Unit 9 opens in the rubble of World War II, as the wartime alliance between the United States and the Soviet Union collapsed into the Cold War — an ideological standoff between capitalist democracy and communism. The Yalta and Potsdam conferences divided defeated Germany and Europe, an Iron Curtain descended across the continent, and the American Truman Doctrine and Marshall Plan committed the West to containing Soviet expansion. Europe split into rival military blocs — NATO and the Warsaw Pact — while Germany and Berlin were physically divided, dramatized by the Berlin Blockade and Airlift and later the construction of the Berlin Wall. Soviet domination of Eastern European satellite states provoked resistance, from the Hungarian Uprising of 1956 to the Prague Spring of 1968, while the nuclear arms race and crises like Cuba kept all of Europe in a state of nuclear anxiety.
At the same time, the war's end triggered rapid decolonization, as European powers lost their empires across Africa and Asia — from the brutal Algerian War of Independence to Britain's withdrawal from India. In Western Europe, the European Economic Community, the welfare state, and West Germany's Wirtschaftswunder drove postwar economic recovery and gradually built the foundations of today's European Union. Postwar society was reshaped by second-wave feminism, immigration and multiculturalism, and the youth protest movements of 1968. The Cold War finally ended as Gorbachev's reforms of glasnost and perestroika unraveled Soviet control, culminating in the fall of the Berlin Wall in 1989, the collapse of the Soviet Union in 1991, and the reunification of Germany — leaving contemporary Europe to grapple with EU expansion, globalization, and ongoing debates over national identity and immigration. This unit is roughly 8–12% of the AP European History exam.
The College Board ties Unit 9 to four of its course-wide themes:
Jump to any unit in AP European History.