Walter Reed National Military Medical Center (WRNMMC; formerly known as the National Naval Medical Center and colloquially referred to as Bethesda Naval Hospital, Walter Reed, or Navy Med) is a United States military medical center located in Bethesda, Maryland. It is one of the largest and most prominent military medical centers in the United States, and it has provided medical care for several United States presidents since its opening in 1940. In 2011, the Walter Reed Army Medical Center (WRAMC), named after yellow fever researcher Walter Reed, was combined with the National Naval Medical Center to form today's tri-service Walter Reed National Military Medical Center.