In 1971, Mrs. Michael Hoff, the wife of a US military officer listed as missing in action during the Vietnam War, developed the idea for a national flag to remind every American of the US servicemembers whose fates were never accounted for during the war.
The black and white image of a gaunt silhouette, a strand of barbed wire and an ominous watchtower was designed by Newt Heisley, a former WWII pilot.
By the end of the Vietnam War, more than 2,500 servicemembers were listed as Prisoner of War or Missing in Action. In 1979, Congress and the president proclaimed the first National POW/MIA Recognition Day. Three years later, the POW/MIA flag became the only flag other than the Stars and Stripes to fly over the White House in Washington, DC.
On August 10, 1990, Congress passed US Public Law 101-355, designating the POW/MIA flag:
"The symbol of our Nation's concern and commitment to resolving as fully as possible the fates of Americans still prisoner, missing and unaccounted for in Southeast Asia".
Congress designated the third Friday of September as National POW/MIA Recognition Day.