The war left most of Germany in ruins. The Allied bombing and invasion had destroyed cities, farms, industries, and transportation. Supplies of food, fuel, and water were very low. People were half starved, and many lived in ruined buildings.

In June 1945, the Allied Big Four—the United Kingdom, France, the Soviet Union and the United States—officially took over supreme authority in Germany. The country was divided into four zones of military occupation, with each power occupying a zone. Berlin, located deep in the Soviet zone, was also divided into four sectors.

In July and August 1945, leaders of the United Kingdom, the Soviet Union, and the United States met in Potsdam, Germany. They agreed to govern Germany together and to rebuild it as a democracy. They also agreed to stamp out Nazism and to settle German refugees from Eastern Europe in Germany. Under the agreement, the Soviet Union also was granted northern East Prussia, which it claimed. The rest of that region, and German territory east of the Oder and Neisse rivers, were placed under Polish control. As a result, Germany lost about a fourth of its land.

Many of the most important Nazi leaders had committed suicide or had disappeared. The Allies brought to trial those remaining. A number of these Nazis were hanged or imprisoned. The most important trials took place in Nuremberg.