There were several factors that caused World War I. One of these factors was imperialism. Germany was a relatively new country. Germany wanted to gain colonies. However, most of the land available for colonization was already gone. In order to get colonies, Germany would probably have to go to war.
Another cause was militarism. Countries were building up their militaries. Usually, there is a purpose for a military buildup. The increasing of the military by several countries led to war.
Another cause of the war was the system of alliances. Two major alliances existed. They were the Triple Alliance that included Italy, Germany, and Austria-Hungary, and the Triple Entente that included France, Great Britain, and Russia. If one member of one alliance declared war on a member from the other alliance, a two-country conflict could quickly escalate. When Serbian nationals killed Franz Ferdinand, the next king of Austria-Hungary, Austria-Hungary eventually declared war on Serbia. Serbia was connected to the Triple Entente with its strong relationship with Russia. After Austria-Hungary declared war on Serbia, Russia declared war on Austria-Hungary. This triggered a domino-like effect with other alliance countries rapidly joining the war.
Finally, nationalism was a factor. People in each country thought their country and way of life was superior to any other country in all respects. As a result, they weren’t afraid of confrontation because they believed they would win any conflict because they were better in all respects than any other country. World War I had several causes.