World War
A world war is a military conflict that affects the majority of the world's countries. World wars usually span multiple continents, and are very bloody and destructive.
The term is usually used to refer to the conflicts World War I and World War II. Both wars occurred in the 20th Century, and involved some degree of participation from most of the world's existing countries. Other wars in earlier periods that saw conflict across the world have been considered world wars, including the Seven Years War (1756-1763).
Since the conclusion of World War II, the world has generally been united by a common desire to never again have another world war.
- World War I (1914-1918)
- World War II (1939-1945)
- World War III (either hypothetical or the Cold War: 1949-1993)
- World War IV (the war on terrorism)