Every year on the last Monday in May, we remember the brave men and women of the U.S. armed forces who gave their lives in service to our country. Through public memorial ceremonies, parades and visits to national cemeteries to place flags and flowers on the graves of the fallen, we pay tribute to their courage and their sacrifice.

“As we conclude this solemn month spent memorializing the many peace officers who gave their all to protect and serve their communities, LAAPOA now joins with the rest of our nation in saluting the brave members of our military throughout history who made the ultimate sacrifice to defend our safety at home and abroad,” President Marshall McClain says. “Whether on duty or spending time with friends and family this Memorial Day weekend, I hope we all can keep the memory of those valiant heroes in our minds and hearts, and give thanks for the freedoms they gave their lives to secure.”

To foster a greater understanding of the traditions and significance of this holiday, we’ve compiled a few interesting facts about Memorial Day.

It’s More Than Just the Start of Summer

The three-day Memorial Day weekend has become known as the unofficial kickoff of summer fun, marked by retail sale shopping, barbecues and vacation getaways. If you’re lucky enough to have the holiday off, it’s natural to think of this as a time for enjoyment — but for military families who’ve lost a loved one and for others who highly value the true meaning of Memorial Day, it can be more sobering. While feelings of joy and gratitude do have their place on this day, be mindful of the serious side as well, and remember that it may not be appropriate to wish everyone a “Happy Memorial Day.”

It’s Different Than Veterans Day…

Many people confuse Memorial Day with Veterans Day, which is observed every November 11. While both holidays commemorate veterans, there’s a key difference: Veterans Day honors all who’ve served, both living and dead, whereas Memorial Day specifically honors fallen military members.

…But They Share a Meaningful Symbol

You might see people donning a red poppy on Memorial Day — a motif dating back to the cataclysmic conflict of World War I, which claimed the lives of nearly nine million soldiers. During the Second Battle of Ypres in western Flanders (Belgium) in 1915, in which some 124,000 were killed, Canadian Lieutenant Colonel John McCrae was tending to the wounded and mourning the dead when he was struck by the sight of vibrant red poppies in bloom across the battlefield. The image moved him to immortalize the moment and pay tribute to the fallen in a poem entitled “In Flanders Fields,” which was published later that year and captured the public imagination as an expression of the destructiveness of the war. In the 1920s, as the world struggled to rebuild and come to terms with the catastrophic losses, American Moina Michael and Frenchwoman Anna Guérin both pushed for the poppy to be adopted by the American Legion and other groups as a symbol of remembrance. Today, millions of people in the United Kingdom, Canada, France, Belgium, Australia and New Zealand wear poppies on November 11, known as Armistice Day, to recognize the end of WWI. In the United States, however, poppies more frequently are worn on Memorial Day to remember all those who died fighting for our country throughout its history.

Memorial Day Started With the Civil War

While there were various days of remembrance for fallen servicemembers from earlier conflicts, such as the American Revolution and the Mexican American War, the profound devastation of the Civil War — estimated to have killed anywhere between 620,000 and 750,000 soldiers, more than 2% of the entire U.S. population at that time — was the impetus for a larger-scale commemoration. There are records of Southern women decorating the graves of Confederate soldiers even before the war had ended, and at least 25 municipalities in both the North and South lay claim to the earliest Memorial Day-style observances, including Boalsburg, Pennsylvania (October 1864); Charleston, South Carolina (May 1, 1865); Columbus, Mississippi (April 25, 1866); and Waterloo, New York (May 5, 1866), which President Lyndon Johnson officially declared the “Birthplace of Memorial Day” in 1966 for its annual community-wide celebration in which businesses closed, flags were lowered to half-staff, and residents placed flowers and flags on soldiers’ graves.

In the aftermath of the war, several groups of Union Army, Navy and Marine veterans united to form the Grand Army of the Republic (GAR), which began as a social organization but soon moved into political advocacy. One of its priorities was to establish an official observance to remember the Union military members who had died in the Civil War. In 1868, the GAR’s commander, General John A. Logan, declared May 30 as that day. The first celebration took place at Arlington National Cemetery, presided over by officials including General Ulysses S. Grant and attended by about 5,000 people. GAR members and the orphaned children of soldiers and sailors who had been killed in the war decorated the graves of the 20,000 Union and Confederate fallen buried there. In a speech, former general and future president James A. Garfield told the crowd, “We do not know one promise these men made, one pledge they gave, one word they spoke; but we do know they summed up and perfected, by one supreme act, the highest virtues of men and citizens. For love of country they accepted death, and thus resolved all doubts, and made immortal their patriotism and their virtue.”

It’s in May for a Reason

It’s no coincidence that nearly all the early memorial observances took place in the spring, when flowers were plentiful, since decorating cemeteries with brilliant blooms was a major component of most celebrations. As Logan proclaimed, “the 30th of May, 1868, is designated for the purpose of strewing with flowers, or otherwise decorating the graves of comrades who died in defense of their country during the late rebellion, and whose bodies now lie in almost every city, village and hamlet churchyard in the land.” Logan chose May 30 specifically because, in addition to being a time when nearly everywhere in the country had access to “the choicest flowers of springtime,” it was not the anniversary of any battle, so it could apply to all fallen soldiers equally.

It Was Known as Decoration Day

Due to the tradition of festooning graves with flags, wreaths and candles, the holiday remembering the Civil War dead was initially called Decoration Day. Local observances gained popularity over the years, and in 1873, New York became the first state to designate May 30 as a legal holiday. Every Northern state had declared it an official state holiday by 1890, and the Army and Navy adopted regulations for proper observances at their facilities. Over time, the name “Memorial Day” gradually eclipsed “Decoration Day,” though that term can still be heard in some areas.

Memorial Day’s Meaning Expanded

It was not until after World War I that the meaning of Memorial Day was broadened to honor those who have died in all American wars. It remained on May 30 until 1971, when the Uniform Monday Holiday Act (passed by Congress in 1968) went into effect, making Memorial Day a national holiday and moving it to the last Monday in May in order to give workers a three-day holiday weekend.

Today, the national observance of Memorial Day still takes place at Arlington National Cemetery, where the president or vice president places a wreath of flowers at the Tomb of the Unknown Soldier, and graves at national cemeteries throughout the country are decorated with flags. And the way we celebrate Memorial Day continues to evolve: In 2000, the National Moment of Remembrance Act was signed into law, encouraging all Americans to pause at 3 p.m. local time on Memorial Day for a minute of silence in honor of those who died for our freedom.