On a recent morning, John Pierce walked across the sprawling hospital campus of the Walter Reed Army Medical Center. On the lawn, he spotted people who have come to define the place in recent years.
"[They were] having physical fitness-type tests," Pierce says. "There were people with notebooks and things, like they record when you do your sit-ups and pushups — but these were a number of double amputees."
Pierce is the historian for the Walter Reed Society, which makes him an expert on the historic American hospital in Washington, D.C.