During the 1920s the American economy increased in strength and the European economy remained stable up until the crash of 1929. In what has become known as The Great Depression many people suddenly found their savings worthless, leading to a disillusionment with capitalism and a rise to prominence of fascism. In 1933 Adolf Hitler rose to power in Germany at the head of his Nazi party.

Hitler began to rearm Germany, and remilitarised the Rhineland in 1936, breaking the Treaty of Versailles. With Hitler's anti-semetic policies and aggressive re-armament of Germany war was inevitable. On 1st September 1939 Germany invaded Poland and Britain and France both declared war on Germany and its allies.

The Second World War would prove to be even more lethal and long-lived than the first war. A global conflict in every sense of the word the war would see an unprecedented number of casualties and would change the world forever.

The Germans took Poland while its government fled to London, and then in May 1940 Germany invaded Belgium, the Netherlands and Luxembourg. Germany was extremely successful in its early expansions and soon also took Denmark and Norway. Within four weeks of their assault Germany had taken France and on 14th of June 1940 Paris was occupied. Soon after Hitler would launch an offensive against Britain, attempting to gain air superiority in order to clear way for an aquatic invasion from France. In what has become known as the Battle of Britain the RAF successfully repelled the German attacks and claimed aerial superiority over England, ending German hopes of invading.

Turning his attention away from Britain, Hitler looked to invade the communist Soviet Union. After a delay in Yugoslavia and Greece after the Italian's defeat Germany assaulted the Soviet Union with the largest army ever known to man. Over three million Germans took part in the invasion, laying siege to Leningrad and getting to within 15 miles of Moscow. The Germans would have to stop for the Russian Winter however, and by Spring 1942 an entire division were trapped in Stalingrad, eventually leading to their surrender. Hitler had seen what should have been a sure victory turn into a defeat. Russian casualties were astronomical, they lost around 27 million people, about half of the total casualties in the war.

As Germany were getting frozen out of the Soviet Union Japan attacked Pearl Harbour, which drew the United States into the war. The Americans, allied with the British and the Soviets would continue to push the German forces back.

On 6th June 1944 the Allies launched an attack onto the beaches of Normandy. The German thought that the Allies would attack Calais and were unprepared for an invasion on the beaches. At a great cost of human life the beach invasion was successful and the Allies were able to push into France. By 1945 the German army was pushed back by the Soviets from the East and the Americans and British from the West. Once the Soviets reached Berlin Hitler committed suicide and seven days later the Germans surrendered, ending the war in Europe. The USA would end the war with the use of nuclear weapons against Japan in Hiroshima and Nagasaki.

After the war the United States and the Soviet Union emerged as the two dominant super-powers, with much of Europe in ruin after the bombing of the war. Many top-ranking German officers were convicted of war crimes, including those committed in the holocaust. During the war the Germans placed millions of Jews and other minorities in concentration camps, starving and eventually murdering them in one of the worst events in human history.

After the use of nuclear weapons by the USA at the end of the war America and the Soviet Union would enter the Cold War, a period of deep mistrust, propaganda, espionage and an arms race in which both countries would be on the brink of war but where fighting never actually broke out. It is thought that the only reason that stopped a war from happening is that a nuclear war would lead to mutually assured destruction and so it was in each country's best interests not to launch missiles. The Cold War would last right up until 1991. After the failure of the League of Nations in preventing World War 2, the United Nations was formed in 1945. The organisation still continues today with nearly every country a participating member.

The next decades are characterised by a growth of technology and industry and the increased Americanisation of the West.