MEMORIAL DAY IS a time to honor those men and women who fought bravely and made the greatest sacrifice one can make to defend liberty: their lives. In all, more than 1.2 million Americans have died in wars since our country was founded.

Too often we take for granted the ideals for which our ancestors fought. It may be easy to forget because only 6% of Americans younger than the age of 65 have served in uniform. It shouldn’t be an inconvenience for us to take a few minutes Monday to honor those veterans.

They were ordinary men and women, many of them just children, thrust into extraordinary circumstances. They bore the burden of defending freedom and our way of life, not just for us, but also for most of the world. They did it for their country, ideals and buddy in the next foxhole.

Before Arlington was a national military cemetery, the Arlington House Estate belonged to the wife of Confederate Gen. Robert Lee, who had inherited it from her father, George Washington’s adopted grandson, according to Shannon Bontrager, a historian and author of “Death at the Edges of Empire.”

In 1864, at the peak of the Civil War, the federal government seized the 1,100-acre property at a tax sale for $26,800 and began burying Union dead there. The estate challenged the confiscation in 1882 and the U.S. Supreme Court returned ownership to the estate. In 1883, it was sold back to the government for $150,000.

Washington’s adopted grandson was George Washington Parke Custis. He was instrumental in designing and building the estate.The original cemetery was 200 acres. It now covers 639 acres. The government built housing for formerly enslaved people who had fled the South seeking freedom. Before long, Arlington’s “Freedman’s Village” had grown to some 3,000 souls.

More than 400,000 are buried at Arlington, and 6,500 are added annually. There are more than 5,000 unknown soldiers buried there. Mary Randolph, cousin of Custis, was the first person buried on the grounds in 1828, before it became a national cemetery.

The first military burial occurred at Arlington in 1864 for Private William Christman. William Taft and John Kennedy are the only former presidents to be buried there. The village of Waterloo, N.Y., holds the designation of being the birthplace of Memorial Day. It started there May 5, 1866.

Establishing a national cemetery and sheltering the self-emancipated at this location served symbolic and political purposes, Bontrager said. It commemorated the death of Union soldiers on land that had once belonged to the leader of the Confederate army.

Also don’t forget, there are major military cemeteries located in 16 foreign countries honoring more than 250,000 American war heroes.

Who we remember and how we remember them is another way of expressing the values we believe are important enough to warrant the sacrifice of human life. Our memorials help to ensure that we remember these deaths as meaningful and justifiable.

Abraham Lincoln was not the first president to grapple with the problem of how to remember those who had died in battle, but he was the most profound. Speaking at Gettysburg, where some 3,000 Union soldiers perished, Lincoln declared the soil on which they fell a sacred site.

He announced that Northern soldiers had died not just to preserve the Union, but to safeguard the principle of liberty, to free the enslaved and, in the process, serve as a model for other nations.

Lincoln said “It was the living who were now obliged to complete the unfinished work which they who fought here have thus far so nobly advanced.” And it was the survivors burdened with grief who were left to “resolve that these dead shall not have died in vain. . . that this nation, under God, shall have a new birth of freedom.”