STOYSTOWN, Pennsylvania — Not far from the entrance to the Flight 93 National Memorial, a quiet stretch of hillside rises gently along the Lincoln Highway. If you drive by too quickly, you might miss it entirely. Yet, this plot of Pennsylvania farmland has transformed into a living sanctuary. It honors not only the souls lost in the catastrophic crash 25 years ago today, but every American service member who has fallen in the subsequent global fight against terrorism.

The mornings across the Appalachian ridges often start heavy and overcast, but today the gray yields to a brilliant, piercing blue sky, punctuated only by light clouds riding the mountain crests.