Why do people fight wars? Sometimes it is to get more land. Sometimes it is to show that your country is strong. Sometimes it is to stop enemies. Some countries put their armies together. They join together to show how strong they are that way. Some want to prove that their country is the best.
Ways of fighting have changed. Armies used to use swords, spears, and arrows. Then guns were invented. When World War One came, there were new weapons. Armies had airplanes, tanks, and deadly gas. The gas was not like what you use in a car. It was like green air. It would sink down to the ground into trenches. The soldiers were in the trenches. The gas made some soldiers sick. It killed others.
Why did World War One start? There were many reasons, but one thing started the fighting. An important man was killed. He was an archduke. He was killed in the region of Bosnia. Bosnia was ruled by Austria-Hungary. The man was supposed to be the next ruler.