Name one war fought by the United States in the 1900s.

The United States was involved in several wars and military conflicts during the 1900s. Here are some notable examples:

• World War I (1917-1918): The United States entered World War I on the side of the Allies in 1917 after remaining neutral for the initial years. American forces played a significant role in the final stages of the war.
• World War II (1941-1945): Following the Japanese attack on Pearl Harbor in 1941, the United States entered World War II. It fought against the Axis powers, including Germany, Italy, and Japan. American forces played a crucial role in the Allied victory in both the European and Pacific theaters.
• Korean War (1950-1953): The United States, along with a coalition of United Nations forces, intervened in the Korean War to support South Korea after it was invaded by North Korea. The war ended in a ceasefire, with Korea remaining divided into North and South.
• Vietnam War (1955-1975): The United States became involved in the Vietnam War to support South Vietnam against the communist forces of North Vietnam. The conflict lasted for two decades and ended with the withdrawal of American troops and the reunification of Vietnam under communist rule.
• Gulf War (1990-1991): The United States led a coalition of international forces in the Gulf War to liberate Kuwait from Iraqi invasion. The conflict was triggered by Iraq's invasion of Kuwait and ended with the expulsion of Iraqi forces.

These are just a few examples of the wars and military conflicts involving the United States during the 1900s. The century witnessed numerous other interventions, conflicts, and military engagements in different parts of the world, including smaller-scale operations and peacekeeping missions.