World war 2 was the most significant part of the 20th century, World war 2 had the most amount of the world involved, with more then 30 countries involved in the war. The only place not involved in world war 2 was Antartica. It was also the deadliest and most horrific war of all time. World war 2 would go on for 6 years (1939-1945). World war 2 took place 2 decades after world war 1.
In 1939 Nazi Germany attacked Poland, this attack caused Britain and France to go to war with Germany. In the early part of the war Nazi Germany began to take over smaller countries, some of these countries were Denmark,Belgium,Luxemburg,The Netherlands, and France. Nazi Germany used a strategy called Blitzkrieg, which used very quick tactics and powerful equipment to quickly wipe out an enemy force. Blitzkrieg succeeded in taking over smaller countries. Hitler the dictator of Germany at the time signed a non aggression pact with Joseph Stalin the dictator of Russia at the time so that Germany wouldn't have to deal with fighting on 2 fronts like world war 1. In 1940 after Germany took over a large amount of small European countries, Hitler began to send bombers to Britain,this moment in the war was called the battle of Britain. Despite being outnumbered The Royal Air Force managed to defend Britain through this battle.Through the beginning of the war The Axis powers which included Germany, Italy, and Japan, and some smaller countries, had the advantage.
At the start of World war 2, America had tried to not be fully involved in the war, at the start it supported the Allied powers which at the end of the war included, America, Britain, France, and Russia, plus smaller countries. America then made the Lend-Lease act, which allowed America to lend weapons and equipment to countries fighting the Axis power, America lended about 50 billion dollars worth of supplies to the Allies. Later in the war in December 7th 1941, the Japanese attacked Pearl Harbor, after the attack the Americans officially joined world war 2.
On June 6th 1944 the Allies executed an invasion now known as D-day, this invasion gave the Allies access to France and take it back from the Axis powers. In the same year a battle called The Battle Of The Bulge was going on, in this battle Germany was running out of soldiers and supplies, but Hitler managed to gain enough troops and leftover supplies to push the allies several miles back for a few months. Near this time Hitler had removed almost all of his military planners and too personal control of the war, but Hitler knew little about war strategy which probably caused the troop and supplies shortage. the Allies won since Hitler could not replace troops as easily as the Allies. This lead to the end of the Axis powers and Germany finally surrendered in 1945. World war 2 officially ended after America dropped two atom bombs on Japan, Japan then surrendered and the war was over.
At the end of World war 2, many places in Europe and Asia were destroyed. Many countries were in horrible war condition due the global great depression. People have estimated that around 75 million people were killed including civilian casualties. Germany alone killed around 15.5 million civilians including the 6 million Jews killed during the holocaust, 3 million soviet prisoners, and many other people included in that. In Japan their was around 14 million civilian casualties, most of this came from forced labor, since Japan made civilians and P.O.Ws or prisoners of war, to do forced labor until they died in labor camps. Russia had the most soldier casualties out of all the countries totaling around 7,500,000 dead and 5,000,000 wounded. The war had killed around 4% of the world population, which at the time was 2 billion.
World war 2 was the breeding ground for modern security, also making America into a modern super power. The war also caused more change than any other war. After the war the Allies had to maintain control in the main Axis powers. After the war, due to many countries being destroyed gave the Soviet Union the ability to take over smaller countries and make them part of the Soviet Union. The Soviet Union began taking over countries and forcing them to have communist governments, the Allies did not agree with this and resulted in the cold war. Germany and Korea were split since half of Germany was controlled by Russia it became part of the Soviet Union, but the other side wasn't owned by The Soviet Union resulting in East and West Germany, North Korea joined the Soviets but not South Korea, Korea is still split today unlike Germany which the problem was resolved in the 90's. All of these events were caused by world war 2, showing how significant it was.