Other forms: civil wars
A civil war is a conflict between groups within a single country, like the American Civil War between the north and south.
Most wars are fought between different countries. However, in a civil war, a country has become divided, and factions within the country are battling each other. One of the most famous examples is the American Civil War (1861-1865), when the southern states fought to leave the U.S., and the northern states fought to keep the country together. A civil war is more painful than other wars in many ways, because the country is literally tearing itself apart.