On Jan. 25, 1961, a special, lead-lined coffin was lowered into a 10-foot-deep grave reinforced with cement at Arlington National Cemetery.

The family of the deceased was told to stand back 20 feet during the service, as a precaution. When the prayers were over, more cement was poured in and the grave filled with earth.

The dead man was Army Specialist Richard L. McKinley, 27, who had been killed in an explosion at a nuclear reactor earlier that month. His body required careful handling.

In the rich lore of Arlington Cemetery — which marks the 150th anniversary of its founding Sunday — McKinley’s burial, as recounted by news articles and historians, is one of the strangest.

Born amid the anguish of the Civil War, the cemetery had long held hallowed remains. This time they were radioactive, too.

This spring, Arlington has been marking its anniversary with special programs and commemorations. An evening musical tribute is scheduled for Sunday, and a public wreath-laying at the Tomb of the Unknown Soldier is set for Monday.

Since 1864, when the bloodshed of the war was sending Washington more dead soldiers than it had graves for, Arlington has been the nation’s most celebrated military burial ground. Tens of thousands of military figures and others, of all ranks, have been laid to rest beneath regiments of white tombstones.

“Hither our children’s children shall come to pay their tribute of grateful homage,” Army general and future president James A. Garfield said at the cemetery on the nation’s first official Memorial Day in 1868, according to the National Park Service.

Over time, Arlington has been a place of national mourning, intimate grief and personal pilgrimage. It has been the venue for solemn memorial pageantry and great solitude.

It’s a quiet spot where the faint sound of Taps, the distant crack of a rifle salute or the clip-clop of a horse-drawn burial caisson can drift on the spring breeze.

In the heat of summer, the air can be thick with the smell of cut grass. In winter, the wind whipping around the ancient oak and walnut trees can be fierce.

In some areas, there are communities of the deceased.

Section 60, in the southeast portion of the cemetery, has become the last resting place of service members killed in the wars in Iraq and Afghanistan and a poignant meeting spot for friends and relatives.

Chaplains Hill, near the center of the cemetery, holds the remains of chaplains who served in four wars. There, among others, rests the Rev. Charles Joseph Watters, a Roman Catholic priest who was given the Medal of Honor posthumously after he was killed while ministering to the wounded in Vietnam in 1967.

In section 21, hundreds of military nurses are buried near the 8-foot marble Nurses Memorial. Gen. John J. Pershing is buried in section 34 overlooking many of his World War I “doughboys” and beside his grandson, Richard, who was killed in Vietnam in 1968.

Although each of Arlington’s 400,000-plus graves mark the tragedy of death, the cemetery also serves as an index of American biography.

“The history of Arlington is really the history of our nation,” Stephen Carney, the cemetery’s command historian, said recently. “Any headstone you go to, if you start researching, you uncover these incredible lives.”

Names of the buried

In a shady grove of trees is the grave of Dwight H. Johnson.

A draftee from Detroit, he was given the Medal of Honor at the White House in 1968 for a breathtaking feat of bravery during the Vietnam War. But he had seen the horror of battle, had come home troubled and was shot and killed while trying to rob a store in 1971. He was 23.

Not far away, along a red brick path in a secluded stand of holly and hemlock trees, is the grave of Abraham Lincoln II, the beloved grandson of the assassinated president.

Young “Jack” Lincoln was a teenager when he died in London of an infection following surgery.

He originally was buried with his grandfather in Springfield, Ill. But on May 27, 1930, his mother quietly moved him to Arlington to rest with his father, Robert Todd Lincoln, a former Secretary of War, who had died four years before.

Jack’s name wasn’t added to Arlington’s massive pink granite Lincoln sarcophagus until 1984, after a researcher noticed the absence of the boy’s name and arranged for its addition, according to news reports at the time.

Elsewhere, more famously buried in the cemetery are slain President John F. Kennedy, his wife, Jackie, and his senator brothers Robert — who also was assassinated — and Edward.

Actor and Marine Corps combat veteran Lee Marvin, acclaimed Supreme Court Justice Thurgood Marshall and boxer Joe Louis rest there, too.

Also buried there are civil rights martyr and Army veteran Medgar Evers, physician Walter Reed and World War II hero Audie Murphy.

And up on the heights, surrounded by a wrought iron fence, is the weathered obelisk marking the 1857 grave of George Washington Parke Custis, the slave-owning aristocrat who built the mansion that gave Arlington its name.

‘The field of the dead’

In the beginning, visitors called the major portion of the cemetery simply “the field of the dead.” The grave markers were of white-washed wood. And there were the remains of 2,111 soldiers in the original tomb of the unknowns.

At one point, during the Civil War, there were as many as 60 burials a day — twice what can be handled today — with bodies pouring from the Virginia battlefields and Washington hospitals.

One witness recalled seeing coffins stacked “like cordwood,” according to a history of the cemetery by Robert M. Poole.

Before the grand funerals of the Kennedys, before Memorial Bridge became the ritual route of the VIP cortege and before the throngs of tourists, buses and jitneys, Arlington was a place to bury the dead because there was nowhere else to put them.

Because of the intensity of the Civil War in the spring of 1864, the cemetery already held more then 2,600 soldier graves when it officially opened June 15, 1864, according to the National Park Service.

Custis, the adopted son of George Washington, had built a hilltop mansion that resembled a Greek temple amid the 1,100 acres of land he owned across the Potomac River from Washington. He called it Arlington, after an older family homestead, according to cemetery historian James Edward Peters.

But Custis’s daughter, Mary Anna, had married a distinguished U.S. Army officer named Robert E. Lee, who had departed with his family after he elected to serve the Confederacy at the start of the Civil War.

And because of its strategic location overlooking Washington, the estate was swiftly occupied by Union forces in May of 1861.

By 1863, the main local military cemeteries in Alexandria and what is now Washington’s Armed Forces Retirement Home were almost full. More space was needed.

The Custis estate on the Potomac seemed perfect. It was a pleasant site. It was on high ground that was unlikely to flood. And it was near hospitals, where many soldiers died.

On June 15, 1864, Quartermaster General Montgomery Meigs ordered: “The Arlington mansion and the grounds immediately surrounding it are by the direction of the Secretary of War appropriated for a Military Cemetery.”

By war’s end there were 13,000 graves at Arlington. The whitewashed headboards bore the names of the deceased in black letters. If the grave contained a Confederate soldier, the headboard simply said “Rebel.”

Becoming a landmark

In 1866, with the war over and the task of locating and burying the scattered dead underway, Meigs ordered that the remains of some of the unknown be sent to Arlington.

Meigs, whose 22-year-old son, John, a Union officer, had been killed in 1864, ordered a 20-foot-deep pit dug near the mansion as Arlington’s first tomb for unknown soldiers, according to Poole’s history and the National Park Service.

“At the time we looked into this gloomy cavern . . . there were piled together, skulls in one division, legs in another, arms in another and ribs in another,” a local reporter wrote of the site before it was finished.

Meigs reported that it held the remains of 2,111 soldiers.

He designed a stone sarcophagus with an inscription noting that although unknown, “their names and deaths are recorded in the archives of their country; and its grateful citizens honor them as of their noble army of martyrs.”

Fifty-five years later, in the wake of another devastating conflict, a horse-drawn caisson bore to Arlington the body of another unknown American soldier, this time from World War I .

The cortege was followed by Pershing and former President Woodrow Wilson — and for a while by President Warren G. Harding, who spoke at the ceremony later.

It was Nov. 11, 1921 — Armistice Day, three years after the end of the Great War. And the burial of the anonymous Yank in the Tomb of the Unknown Soldier signified, in a way, the coming of the U.S. and the cemetery to the world stage.

Harding’s address was broadcast across the country, the first time for a presidential speech, Poole recounted.

And when the somber theater of John F. Kennedy’s 1963 funeral was beamed around the world on television, Arlington became an international landmark.

Within 11 months after the president’s funeral, more than 7 million people visited his grave, said Carney, the cemetery command historian.

Most people who visit Arlington now don’t know anyone buried there. But there is a kinship gained in paying respect. And in return, the cemetery requires reverence of its visitors.

“Here is our temple,” Garfield said in 1868. “Its dome [is] the bending heavens, its altar candles the watching stars.”