World war

United States Army infantry supported by a M18 tank destroyer advancing through an enemy-occupied town during World War II.

A world war is an international conflict in which most of the countries in the world fight or help.

There have been four world wars so far, World War I (1914-1918), World War II (1939-1945), the Cold War (1945-1992), and the War on Terror (2001-present).

After World War II, many people were scared that fighting would start from the Cold War between the United States and Western Bloc on one side and the Soviet Union and Eastern Bloc on the other. After World War II, countries had many powerful weapons, including jet bomber airplanes, which could carry nuclear weapons to destroy many buildings and kill many people instantly, far away; and much faster missiles which could also carry nuclear weapons.