(CNN)Here's a look at what you need to know about Memorial Day, a day honoring American soldiers who died serving the country in wars. In 2015, Memorial Day will be on May 25.
Celebrated on the last Monday in May.
Several towns claim to be the originators of Memorial Day but in 1966, Congress declared Waterloo, New York, to be the birthplace of the holiday.
Memorial Day originally honored military personnel who died in the Civil War (1861-1865).
The holiday now honors those who died in any war while serving with the United States.
It is also called Decoration Day.
May 5, 1866 - Residents of Waterloo, New York, observe a Memorial Day in honor of all who died during the Civil War. Businesses are closed and soldiers' graves are decorated.
1868 - General John Alexander Logan officially proclaims May 30, 1868 as Memorial Day in honor of the Union soldiers who died in the Civil War. Until after World War I, southern states celebrate a separate Memorial Day in honor of the Confederate dead.
1971 - Congress declares Memorial Day a national holiday to be celebrated the last Monday in May.
U.S. War Casualties:
Civil War - Approximately 620,000 Americans died. The Union lost almost 365,000 troops and the Confederacy about 260,000. More than half of these deaths were caused by disease.
World War I - 116,516 Americans died, more than half from disease.
World War II - 405,399 Americans died.
Korean War - 36,574 Americans died.
Vietnam Conflict - 58,220 Americans died. More than 47,000 Americans were killed in action and nearly 11,000 died of other causes.
Operation Desert Shield/Desert Storm - 148 U.S. battle deaths and 235 non-battle deaths.
Operation Iraqi Freedom - 4,424 U.S. service members died.
Operation New Dawn - 66 U.S. service members died.
Operation Enduring Freedom - 2,355 U.S. service members have died as of December 31, 2014.