WASHINGTON – The surprise military attacks by the Viet Cong and the North Vietnamese people’s army against the South Vietnamese army, U.S. forces and their allies became known as the Tet Offensive. The events of the deadly Tet Offensive that changed the Vietnam War were captured through the lens of then 20-year-old photographer John Olson. The Newseum is showcasing 20 of Olson’s photographs to mark the 50th anniversary of the Tet offensive.