Vietnam War

Raul Guerra was adopted, so his DNA couldn't be matched to blood relatives. Scientists instead turned to an emerging technique that linked his bones to the drinking water in the places he grew up.

"Ring of Red: A Barrio Story" relies on oral histories to tell the rarely heard stories of Mexican-American veterans.

In the Vietnam War era, Americans became more interested in recovering missing troops -- largely because of the activism of some military families.

The well-equipped medevac helicopters that transported injured troops in Vietnam became the model for today's air ambulance services in the U.S.

The ten-part documentary by filmmakers Ken Burns and Lynn Novick is at times graphic, and people who work with veterans say it may trigger traumatic memories for those who fought in Vietnam.

For U.S. troops in Vietnam, the "China Beach" surfing spot provided a rare recreational outlet during the war. Some still seek healing from the waves.

As the nation prepares to commemorate Memorial Day, more than 1600 service members remain unaccounted for from the Vietnam War. For the families of some of them, the search for answers has become a lifelong pursuit.