In particular, during the Vietnam War, Langley Air Force Base was a designated 'waiting base' and thousands of Air Force families were transferred to Hampton from all over the world to wait while their husbands and fathers served in Vietnam. Thousands of Navy families associated with Naval bases in Norfolk next door also waited in Hampton during this era. Vietnam was a very high casualty war for Air Force and Navy pilots (some types of planes experienced a 50% casualty rate), and Naval "river rats" who fought on the rivers of the Mekong Delta experienced high casualties as well. There accumulated over time, in the Hampton area, a high concentration of families of unaccounted for wartime casualties. In many cases Hampton-stationed military families of "Missing in Action" or "Prisoner of War" pilots and sailors spent many years in the area waiting to find out what had happened to their missing or captured airmen and sailors.