Memorial Day, originally called Decoration Day, is a day of remembrance for those who died in service to their country. The holiday was officially proclaimed in 1868 to honor Union and Confederate soldiers and was expanded after World War I to honor those who died in all wars. It became an official federal holiday in 1971, known as Prayer for Peace, Memorial Day. Today, Memorial Day honors over 1 million men and women who have died in military service since the Civil War began in 1861.

From The American Presidency Project, Proclamation 2889—Prayer for Peace, Memorial Day (1950): “Since war is the world's most terrible scourge, we should do all in our power to prevent its recurrence.

“It was the hope of mankind that with the cessation of hostilities of World War II the way would be open to founding a permanent peace. Instead, that war has left the world in a state of continued unrest. Accordingly, we feel the need of turning in humble suppliance to Almighty God for help and guidance.

“In recognition of this need, the Congress has fittingly provided, in a joint resolution which I approved on May 11, 1950, that Memorial Day, which has long been set aside for paying tribute to those who lost their lives in war, shall henceforth be dedicated also as a day for Nation-wide prayer for permanent peace. The Congress has also requested that the President issue a proclamation calling upon the people of the United States to observe Memorial Day in that manner.”

The first veterans of the United States served during the American Revolution in the Continental Army, created in 1775 when colonial militias formed a common army under command of George Washington. Since then, the United States has declared war 11 times and fought in conflicts around the world. More than 41 million Americans have served over the course of the nation’s history. More than 16 million did so in World War II alone.

Who are America’s veterans? Throughout history, they have included the Green Mountain Boys, Buffalo Soldiers, Tuskegee Airmen, Women Airforce Service Pilots, Screaming Eagles, and Green Berets. They are the men and women who served their country at home and abroad, on land, sea, and air—and since 1973, have served as an all-volunteer force. Roughly 18 million Americans, or about 7 percent of the adult population, who were veterans of the U.S. Armed Forces in 2018. Ranging from 18 to over 100 years old, they served in conflicts as diverse as the Korean War and the Global War on Terrorism.