(NewsNation) —  Since 1868, when it debuted as Decoration Day, Americans have been honoring the men and women who gave their lives while serving the nation’s military. Now known as Memorial Day, the holiday not only commemorates the sacrifices of fallen service members but celebrates the lives they led and families they left behind.

At the U.S. Naval Academy the Friday before Memorial Day, a celebration of a new class of officers comes with acknowledgment of the sacrifices of those before them, not far from these graduates’ minds.

“Midshipmen, for the rest of your careers, you’re going to face challenges unforeseen,” President Joe Biden said at this year’s ceremony. “You’re going to have to adapt. Be ready to lead your people through whatever lies ahead.”

They move forward in their careers on the shoulders of the more than 645,000 service members since World War I who could not.

Some of those Americans’ lives were honored with a simple flag alongside each headstone at Arlington National Cemetery, planted there by people who wear the uniform today.

“Every one of these headstones represents an individual who meant something to someone,” said Capt. Andrew Katz, 3rd Infantry Regiment, speaking on “Rush Hour” Friday.

“I respect everyone who has served before me. The ones who have fallen before us. I take that day in remembrance of them,” said 20-year-old Airman Autumn Branch.

“We’ll never necessarily be able to fully thank these heroes, but it’s important that we make the effort,” Katz said.  

In the nation’s capital this weekend, a wall of poppies will be on display. That flower has come to signify the ultimate sacrifice of service members.