World War II

World War II, or the Second World War, lasted from September 1, 1939, to September 2, 1945. It was a global conflict between two major groups of countries: the Allies and the Axis powers. Almost every country in the world took part in this enormous war.

New kinds of fighting, like using tanks and aircraft, changed how battles were fought. For the first time, nuclear weapons were used in war. Sadly, World War II was the deadliest war in history, with around 60 to 75 million people losing their lives.

The war began when Nazi Germany, led by Adolf Hitler, invaded Poland in 1939. This led the United Kingdom and France to declare war on Germany. Over the next few years, the fighting spread around the world. In 1941, Germany invaded the Soviet Union, and Japan attacked the United States at Pearl Harbor in Hawaii, bringing the U.S. into the war.

The war ended in 1945. Germany surrendered unconditionally in May after the Allies invaded France at Normandy and captured Berlin. Later that year, the U.S. dropped atomic bombs on the Japanese cities of Hiroshima and Nagasaki, leading Japan to surrender unconditionally in August.

World War II changed the world forever. It led to the creation of the United Nations to help keep peace between countries. The war also marked the start of the Cold War between the Soviet Union and the United States, and led to many countries gaining independence after European powers lost much of their influence.

Start and end dates

Most historians agree that World War II began with the German invasion of Poland on 1 September 1939. The British and French then declared war on Germany. The war ended with the armistice of 15 August 1945, known as V-J Day, and the formal surrender of Japan on 2 September 1945.

See also: List of timelines of World War II

Background

Main article: Causes of World War II

World War I changed Europe greatly. Many countries lost land, and new nations formed from old empires. To avoid another big war, the League of Nations was created. It aimed to keep peace by talking things out and making sure countries followed the rules.

However, some nations felt unhappy. Germany lost land and money after World War I and wanted to get back what it had lost. In Italy, leaders wanted to make their country powerful again. In Asia, Japan wanted to control more land, especially in China. These feelings and actions helped set the stage for World War II.

Pre-war events

Italian invasion of Ethiopia (1935)

Main article: Second Italo-Ethiopian War

The Second Italo-Ethiopian War was a colonial war that began in October 1935. It started when Italy invaded Ethiopia from its colonies in Italian Somaliland and Eritrea. This war led to Ethiopia being occupied and joined into a new Italian colony called Italian East Africa. It also showed that the League of Nations, which was supposed to keep peace, was not strong enough to stop the invasion.

Spanish Civil War (1936–1939)

Main article: Spanish Civil War

A civil war broke out in Spain between the government and rebels led by General Francisco Franco. Germany and Italy supported the rebels, while the Soviet Union supported the government. Many people from other countries also joined to fight for the government. The rebels won in 1939, and Franco became the leader of Spain.

Japanese invasion of China (1937)

Main article: Second Sino-Japanese War

In 1937, Japan started a war with China after an incident at a bridge. Japan quickly took over many cities, including Peking and Shanghai. China’s leader, Chiang Kai-shek, moved his government to a safer place and kept fighting. Japan tried to break the spirit of the Chinese people by bombing cities, but Chinese resistance continued.

Soviet–Japanese border conflicts

Main article: Soviet–Japanese border conflicts

In the late 1930s, there were small battles between Japan and the Soviet Union near the border. These battles happened while Japan was also fighting in China. In 1939, Japan lost a big battle and decided to focus its expansion southward instead of north.

European occupations and agreements

In Europe, Germany became more aggressive. In 1938, Germany took over Austria and part of Czechoslovakia. Other countries like Britain and France agreed to let Germany have some land to avoid a bigger war, but Hitler was not satisfied. In 1939, Germany took the rest of Czechoslovakia and made demands on Poland. This led to tensions that eventually resulted in the start of World War II.

Course of the war

The Second World War lasted from September 1, 1939, to September 2, 1945. It was a global conflict between two main groups: the Allies and the Axis powers. Almost every country in the world was involved in some way.

The war began when Germany invaded Poland in September 1939. This led Britain and France to declare war on Germany. The conflict spread quickly, with major battles happening in Europe, Africa, Asia, and the Pacific. New technologies like tanks and airplanes changed how wars were fought. Cities were bombed from the air, and the war saw the first and only use of nuclear weapons in combat. The war ended with the defeat of the Axis powers and the beginning of a new world order.

Main article: European theatre of World War II

Main article: Western Front (World War II)

Main article: Mediterranean and Middle East theatre of World War II

Main article: Eastern Front (World War II)

Main article: Pacific War

Aftermath

Main articles: Aftermath of World War II and Consequences of Nazism

After World War II, the countries that won the war, called the Allies, set up occupation areas in Austria and Germany. Germany was split into zones controlled by different Allied powers, eventually becoming two separate countries: West Germany and East Germany. Austria remained under occupation until 1955, when it became an independent country.

To help keep peace, the Allies created the United Nations in 1945. The five main Allied powers became permanent members of the UN's Security Council. The world was divided into two groups, led by the United States and the Soviet Union, starting what is known as the Cold War. This led to many political tensions and competitions over the next several decades.

Impact

Main article: Historiography of World War II

World War II was a huge conflict that caused many changes around the world. Millions of people lost their lives, and many countries faced serious challenges. The war showed how important new technologies like airplanes and tanks could be in battles.

The war led to big changes in how countries worked together and how they prepared for future conflicts. It also highlighted the need for better ways to keep people safe and make sure wars like this do not happen again.