- Many countries disappeared and others were born:
- Countries disappeared: Russian Empire, Ottoman Empire, Bosnia, Serbia, Austria_hungary, German Empire, Montenegro.
- Countries Changed: Great Britain, Romania, Germany, France, Austria, Hungary, Italy.
- Countries Created: Turkey, Iraq, Lebanon, Cyprus, Iran, Yugoslavia, Hungary, Austria, Czechoslovakia, Danzig, Albania, Ireland, Poland, Lithuania, Latvia, Estonia, Finland.
- It was one of the main reasons for the Soviet Revolution in Russia.
- The USA was involved in this originally European war.
- Nazism was born after the Treaty of Versailles.
- Before the war, most women were housewifes. As men went abroad to fight, many women started to work in factories, shops and offices. Women kept economy moving. After the war many women lost their jobs but many others kept them. Read more.
- Aircrafts became essential to help ground troops.
- Tanks were used.
- Armies were more mobile.
- The submarine and automatic rifles were first used as weapons.
- The economy of the USA benefited from the war whereas German economy suffered after the war.