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Key points

  • When World War Two ended in 1945, there was hope that the wartime allies - the UK, America and Soviet Union - could work together to build a peaceful future.
  • However, relations between the US and the Soviet Union quickly deteriorated, leading to 45 years of tension, a nuclear arms race and a constant threat of nuclear war.
  • Communism and capitalism are opposite .

Video about the Cold War

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Key events in the early years of the Cold War

Timeline of Cold War events 1945-55 - Yalta conference, Potsdam conference, Marshall Plan, Truman Doctrine, Churchill's Iron Curtain speech, Berlin Blockade, Formation of NATO and the Warsaw Pact.
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The Yalta Conference

In February 1945, the leaders of the UK, America and the Soviet Union met in Yalta in the Crimean region of the Soviet Union. After winning World War Two, these powers became known as the Big Three. They met to discuss what would happen in Europe after Nazi Germany was defeated.

Joseph Stalin (Soviet Union), Franklin Roosevelt (USA) and Winston Churchill (UK)decided that Germany would be split into four zones. The Soviet Union, USA, UK and France would each control a zone. The German capital Berlin, which was in the Soviet zone, would also be divided into four.

A map of post-World War 2 Germany, showing it divided into the US, French, British and Soviet zones. Berlin is in the Soviet zone, but is divided into US, French, British and Soviet sectors

It was also decided that there should be free and fair elections in Eastern European countries that were now free from Nazi control. In the meantime, the Soviet Union was to be allowed a 鈥榮phere of influence鈥 over these countries, where values would dominate.

The Soviet Union also agreed to support the USA in the war against Japan.

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The Potsdam Conference

The Big Three met again five months later in Potsdam, just outside of Berlin, in July 1945. Things had changed a lot since the Yalta Conference. Nazi Germany had been defeated and the war in Europe was over.

There had been a change in leaders too. The British Prime Minister, Winston Churchill, had lost a general election and had been replaced by Clement Attlee. The American President Franklin Roosevelt had died and was replaced with Harry Truman. This change in leadership meant that a lot of the personal relationships were lost.

Truman thought Roosevelt had been too lenient with Stalin and communism. During the conference, he found out that an American test of the had been successful. This meant he no longer needed Soviet help in the war against Japan. Truman also felt that Stalin was failing to keep the agreement made at the Yalta Conference, that there would be free and fair elections in Eastern Europe.

The Potsdam Conference formally agreed the division of Germany into four zones, but failed to settle other important issues. Some historians have argued that these tensions between the Big Three helped to set the stage for the Cold War.

What were the differences between the Yalta and Potsdam conferences?

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Soviet control in Eastern Europe

Between 1945 and 1949, Stalin worked on putting Soviet-friendly governments into Eastern European countries, such as Poland, Romania, Czechoslovakia and Bulgaria. Opponents to the Soviets were arrested and many elections were rigged.

Stalin argued that Russia had been attacked twice by Germany in the twentieth century, so a around Russia would help to protect them.

Winston Churchill gave a speech in 1946 saying 鈥渁n Iron Curtain has descended across Europe.鈥 This phrase became commonly used to explain the divide in Europe, between a communist and a .

A map of Europe in the 1940s and 1950s showing capitalist and communist countries, divided by the Iron Curtain.
Figure caption,
A map of Europe in 1949, with the Iron Curtain separating east and west
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The Truman Doctrine and Marshall Plan

America was concerned about the spread of communism and feared the Soviet Union would take advantage of the poverty in Eastern European countries that were still recovering from the effects of World War Two. There were also concerns that western countries such as France or Italy may turn to communism as they looked to recover from the war.

Harry Truman gave a notable speech in 1947 called the 鈥楾ruman Doctrine鈥. In this speech, he pledged that America would do whatever they could to support European countries and stop the spread of communism, pledging $400 million to Greece and Turkey for economic and military aid.

This was followed up in 1948 with the Marshall Plan. General George Marshall visited European countries to see the extent of the support needed for their recovery. Marshall had been Chief of Staff in the American army in World War Two and was then appointed Secretary of State. He had seen first-hand the damage that the war had done to European countries.

A system was set up where countries could apply for loans from America. In total, around $13 billion was given out across Europe in grants and loans. Stalin forbade any eastern bloc countries from accepting the offer of aid, claiming that the Marshall Plan was a way for America to interfere with the domestic affairs of other countries.

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The Berlin blockade and Airlift

The was highly effective in helping the western zones of Germany to make a strong economic recovery. The countries who controlled the western zones - America, UK, and France - introduced a new currency, the Deutsche Mark, in an attempt to settle the economy down. But this angered Stalin. At the Yalta Conference it was agreed they would work towards reuniting Germany 鈥 and the new currency in the American, French and British zones made this less likely.

In response, Stalin blocked all land borders into West Berlin. This stopped food, medicine and supplies being transported into western zones by road, railway or canal. Some historians believe that Stalin was hoping the western allies would abandon their zones in Berlin.

General Clay, who was in charge of the American troops in Berlin, wanted to break through the blockade. He believed that the Soviet Union would not dare risk war as America was the world鈥檚 only nuclear power at the time. He was persuaded by his superiors against this course of action and instead America, the UK, and France launched an airlift from the west German zones into West Berlin. They carried in coal, food, medicine and other supplies the people of West Berlin needed. At the height of the Berlin Airlift, a plane was landing in West Berlin every minute.

Stalin did not shoot down these planes as they were flying in air corridors that had been agreed at the Yalta Conference. He also didn鈥檛 want to risk a war with America.

After eleven months, the Soviets realised that America would not give up West Berlin, so the blockade was lifted on 12th May 1949. It was a major propaganda victory for the West and Berlin became a symbol of the allies鈥 keenness to oppose further soviet expansion. The Soviets had failed in their objective of forcing the UK, America, and France out of West Berlin.

A group of people in West Berlin watch as a US plane flies overhead.
Image caption,
West Berliners watch on as a US plane brings supplies to Tempelhof Airport during the Berlin Airlift
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NATO and the Warsaw Pact

In April 1949, twelve countries joined the North Atlantic Treaty Organisation (NATO). The founding members were the UK, America, France, Belgium, Canada, Denmark, Iceland, Italy, Luxembourg, the Netherlands, Norway and Portugal.

The key agreement was the principle that an attack on one member would be considered an attack on them all. This was seen as a way to protect western countries against Soviet aggression. West Germany joined NATO in May 1955 after the UK, France and America ended their military occupation of their respective zones in West Germany.

In response to West Germany joining NATO, the Soviet Union set up the Warsaw Pact in May 1955.The Warsaw Pact had eight founder members: the Soviet Union, Albania, Bulgaria, Czechoslovakia, East Germany, Hungary, Poland and Romania. They also made a similar commitment to defend each other.

Who was to blame for the start of the Cold War?

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Activity - order these events

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Test your knowledge

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Play the History Detectives game! game

Analyse and evaluate evidence to uncover some of history鈥檚 burning questions in this game.

Play the History Detectives game!
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