Not much, of course, was left after the crash except debris from the aircraft and some personal belongings. Mr. Miller said that only 8 percent of the human remains were ever recovered because the plane, roaring down at more than 570 miles per hour, exploded when it crashed. “Everything vaporized on impact,” he said.

Yes, human remains were recovered from the Flight 93 crash site near Shanksville, Pennsylvania, but the identification process was exceptionally difficult due to the high-speed impact and intense heat of the explosion. The Somerset County Coroner, Wallace Miller, and forensic teams managed to recover and eventually identify remains for all 40 passengers and crew members through DNA testing and dental records by late 2001. However, because the impact "vaporized" much of the aircraft and its occupants, only about 8% of the total human remains were ever physically recovered. The remaining unidentified fragments were collected and placed in three caskets, which were eventually buried in a private ceremony at the crash site in September 2011. Today, the "Field of Honor" at the National Memorial marks the final resting place of these heroes; the actual crash site, known as the "Sacred Ground," is protected and accessible only to family members, as it is legally and culturally considered a cemetery for those whose remains could not be individually returned.