Maj. Gen. Brian Lein, commanding general, U.S. Army Medical Research and Materiel Command and Fort Detrick, views a stereoscopic medical illustration through a 19th century stereoscope during a tour of the National Museum of Health and Medicine in Silver Spring, Maryland. The stereoscope card Lein viewed is among the holdings of the NMHM's Otis Historical Archives. The NMHM is the Department of Defense's medical museum and is an element of the USAMRMC. (Photo by Matthew Breitbart, NMHM)