WASHINGTON - Chaplains and religious affairs specialists from across the Military District of Washington gathered May 21 at Chaplains Hill, where they honored the fallen buried in Section 2 of Arlington National Cemetery, by placing flags at their gravesites prior to Memorial Day weekend, in a tradition known as Flags In.Chaplain (Maj. Gen.) Thomas L Solhjem, U.S. Army chief of chaplains, placed the first flag at the headstone of Chaplain (Maj.) Charles Joseph Watters, who served in Vietnam and posthumously received the Medal of Honor for his selfless actions on Nov. 19, 1967.During Flags In, Soldiers place small American flags in front of more than 228,000 headstones, as well as at the bottom of about 7,000 niche rows in the cemetery's Columbarium Courts and Niche Wall. Each flag is inserted into the ground, exactly one boot length from the headstone's base.Someone visits the headstone of every person buried at Arlington during Flags In, and this year is no different, even though the cemetery is currently closed to the public.”Every hero that is here will have someone standing in front of their headstone, placing a flag, reading their name, and thinking about them for that moment,” said Chaplain (Maj.) Joseph Mason, chaplain with the 3rd U.S. Infantry Regiment. “It’s an honor for us to be a part of that. For me, to take on that mission is very meaningful."The 3rd U.S. Infantry Regiment (The Old Guard) has conducted Flags In since The Old Guard was designated as the Army's official ceremonial unit in 1948, according to Arlington National Cemetery's website.Army chaplains place flags in front of the headstones and four memorials located on Chaplains Hill in Section 2. The memorials honor the chaplains killed in World War I; Protestant chaplains killed in World Wars I and II; Catholic chaplains killed in World War II, Korea and Vietnam; and Jewish chaplains killed while on active duty.All flags are removed after Memorial Day.