Arlington, Virginia (CNN) -- Under an almost cloudless sky, family members gathered and soldiers marched in full military dress. Taps echoed in the wind. A wreath of red, white and blue flowers was placed on a grave.
It is a solemn ritual repeated multiple times daily, year-round at Arlington National Cemetery outside Washington. But this ceremony on Tuesday at the resting place of Army Pvt. William Christman carried particular significance.
Christman, a civil war soldier, was the first to be buried at Arlington and the graveside remembrance was held to mark the start of the cemetery's 150th anniversary commemoration, which will continue through June 16.
Over that century-and-a-half, more than 400,000 active duty service members, veterans and their families have been buried there, according to the cemetery's website.
Presidents, astronauts, Supreme Court justices and other notable Americans also have been laid to rest at Arlington.
"It's a place that is consecrated by all the heroes that are buried here," said Jack Lechner, the cemetery's deputy superintendent. "We have heroes here from every war that the United States has fought in from the Revolutionary War on."
The initial property belonged to George Washington's extended family and then to Robert E. Lee, who left it at the start of the Civil War. Federal troops used it as an encampment, and the federal government purchased 200 acres in 1864 and established a cemetery.
More than 600 acres now, Arlington is mostly known for dignified rows of white marble headstones that sweep down an expansive, rolling tree-lined slope where the hallowed ground almost touches the Potomac River.
The cemetery is also a year-round tourist attraction with 250,000 visitors each month. Many flock to the most well-known grave -- that of President John F. Kennedy. It is marked by the flickering "eternal flame."
For Phil Doyle and his family, visiting from Australia, it was one stop they knew had to be made especially with one of their sons training to be a helicopter pilot in the Australian Forces.
"It's an emotional thing walking in and seeing all the tombstones. It really hits you hard," said Doyle. "It's one of enormous sacrifice by so many people."
Rebecca McCarley, a police officer from Oklahoma City, has visited the cemetery before and says she is overcome by feelings of extreme gratitude.
"It is absolutely awe inspiring the change of the guard by the Tomb of the Unknown. It's such a huge sacrifice people made so that we could be free."
Barbara Christman Page, Christman's great-grandniece, had been to the cemetery before. But she was never aware there was a family grave site, something she will make sure to change for her grandchildren.
"It is so important. It also made us think that we need to pass this story on as opposed to just letting it stop right here," Page said. "We are going to make sure that they know. We will probably bring them back so they, too, can visit William's grave."