ELI5: Explain Like I'm 5

World War III

World War III is an idea of a huge, global war involving a lot of different countries. It hasn't happened yet, but it's something that people worry about. In World War II, a lot of countries fought each other and there were a lot of battles and bombings. A WWIII could be even bigger and more destructive than that, with even more people, countries, and weapons involved. The only way to prevent it is for countries to work together and try to solve any problems that arise between them without hurting each other.