The Old Guard places flags for fallen heroes at Arlington National Cemetery

As we enter this Memorial Day weekend, a solemn task is underway to honor veterans who made the ultimate sacrifice. Soldiers from the U.S. Army's Old Guard are fanning out across Arlington National Cemetery.

Their mission? To render a simple, but heartfelt honor to everyone buried at America's hallowed grounds.

But the meaning of all this is much deeper. It insures each person buried here is directly honored during the Memorial Day holiday.

Arlington National Cemetery is bustling with the activity of a military mission. It is called "Flags-In." Over four hours on Thursday, more than a thousand U.S. Army Old Guard soldiers placed a small American flag at more than 228,000 graves.

It is a 60-year-old tradition that is steeped in both tradition and logistics.

"It takes about four month to plan prior to the execution of what we call ‘Flags-In,'" Maj. Tim Meadors. "And that planning is sectioned off in all of Arlington National Cemetery, then assigning all of our companies and our two battalions to specific areas within Arlington National Cemetery."

It literally takes an Army to do this job. Every available soldier in the 3rd U.S. Infantry Regiment takes part. They place the flag and the move on to the next. They will do this over and over again until the entire every flag is placed.

Arlington officials say "Flags-In" draws the cemetery largest crowds of the year.

"We're expecting about 250,000 people this weekend," said Jennifer Lynch, spokesperson for Arlington National Cemetery. "This is probably one of our busiest time of year. People come to Arlington to honor the fallen, visit their loved ones and pay homage to those who have served and paid the ultimate sacrifice."

It is a remarkable work pace. On average, you will see a flag placed 16 times a minute. That is nearly 250 flags every 15 minutes.

This means that each and every grave here is rendered direct and personal honors this weekend. It is a fitting memorial to America's military dead at a place where Memorial Day never really ends.

They began placing the flags at exactly at 4 p.m. Thursday.

The Old Guard told us these flags will remain in place here through the weekend through Memorial Day.

They will then be removed in exactly the same manner in which they were placed starting Tuesday morning.