There’s a unique way to fly the flag for Memorial Day: Do you know it?

Memorial Day is one of just six occurrences when the flag is flown differently than normal.

(NEXSTAR) — Memorial Day has a relatively simple purpose: honor those who have died in American wars. What isn’t as simple is how the American flag should be flown to mark the holiday. 

Three years after the Civil War ended, Decoration Day was established. It was intended as a time for the nation to decorate the graves of the war dead with flowers, according to the U.S. Department of Veterans Affairs. It was later set for May 30 to correspond with flowers being in bloom. Years later, the holiday would be renamed Memorial Day.

According to the VA, while about 25 places have been named in connection with the origin of Memorial Day, the official birthplace was declared Waterloo, New York, by Congress and President Lyndon Johnson in 1966. A ceremony was held there on May 5 of that year, honoring local veterans who had fought in the Civil War. Businesses closed and flags were flown at half-staff.

Up until the end of World War I, the day continued to honor those who had fought in the Civil War. In 1971, Memorial Day was declared a national holiday by Congress, placing the day on the last Monday in May to honor those who have died in all American wars. For many, part of honoring those individuals entails flying the flag proudly in their front yards. 

However, according to the United States Code, Old Glory is flown a little differently on Memorial Day. 

The code — which officially addresses dozens of subjects — says the American flag should fly at half-staff from sunrise until noon on Memorial Day. Then, it should be “raised briskly” to the top of the staff until sunset, according to the VA.

This is one of only six occurrences in which the flag flies at half-staff. The others are the recently-observed Peace Officers Memorial Day on May 15, as well as Korean War Veterans Armistice Day on July 27, Patriot Day on September 11, Pearl Harbor Day on December 7, and any day when the president issues an order lowering the flag as a mark of respect for the death of a principal figure or others, the American Flagpole & Flag Co. explains. 

Whether the flag is flying at half-staff or full-staff, it should only be displayed from sunrise to sunset on buildings and on stationary flagstaffs in the open. When raised, it should always be done briskly; when lowered, it should be done so ceremoniously. If illuminated at night, the flag can remain up at all times. 

American flags on walls should be hung so the union, or stars, are in the top left corner. The same should be said for those hanging in windows — but the union should be in the upper left corner for those viewing it from the outside. 

In only one situation can a flag or pennant be displayed above the U.S. flag: During church services conducted at sea by naval chaplains for personnel of the Navy, the church pennant may appear above the American flag.