The American Civil War was fought between the Union (the northern states) and the Confederacy (the southern states) over the issue of slavery.

World War II was the deadliest conflict in human history, with an estimated 50 to 85 million fatalities.

The Korean War was a conflict between North Korea and South Korea, supported by the Soviet Union and China, respectively.

The Persian Gulf War was a conflict between Iraq and Kuwait, with the United States and its allies intervening to liberate Kuwait.

The War in Afghanistan was a conflict between the United States and its allies and the Taliban.

The Russo-Ukrainian War is an ongoing conflict between Russia and Ukraine, with Russia annexing Crimea and supporting separatists in eastern Ukraine.

The French and Indian War was a conflict between the British and the French over control of North America.

The Spanish-American War was a conflict between the United States and Spain over control of Cuba and other Spanish colonies.

The Mexican-American War was a conflict between the United States and Mexico over the annexation of Texas.

The War of 1812 was a conflict between the United States and Great Britain over trade and territorial disputes.

The Pacific War was a conflict between the United States and Japan over control of the Pacific Ocean.

The Vietnam War was a conflict between the United States and Vietnam over the reunification of Vietnam.

The Gulf War was a conflict between the United States and Iraq over Iraq's invasion of Kuwait.

The Libyan Civil War was a conflict between the Libyan government and rebel forces, with the United States and its allies intervening to support the rebels.

The Syrian Civil War is an ongoing conflict between the Syrian government and rebel forces, with the United States and its allies intervening to support the rebels.