The Best Episodes Directed By Brian Knappenberger

The USSR's grasp on Eastern Europe weakens as the Berlin Wall comes down and the Communist Party mounts a coup against a prominent Soviet Union leader.

Vietnamese soldiers recall the origins of their brutal conflict across the 17th parallel. The US Civil Rights Movement inspires a new wave of activists.

"In the end, the human toll is enormous." The legacy of the war extends far beyond the fall of Saigon. History repeats itself in Iraq and Afghanistan.

A new Russian leader emerges, and the republics seek independence. As the Soviet Union dissolves, several powers sign a landmark treaty on nuclear arms.

With no cohesive strategy, the war in Afghanistan squanders early successes and backfires, fueling disillusionment, corruption and a Taliban resurgence.

Interviews and chilling archival recordings chronicle the chaos that unfolded during the 9/11 attacks, whose origins can be traced to the 1980s.

Learning the hijackers benefitted from gaps in US intelligence, the White House justifies a secret surveillance program and "enhanced interrogation."

Survivors recount the horrors they endured on 9/11. Immediately after the attacks, George W. Bush begins charting America's aggressive military response.

After two decades, the US aims to end its longest-ever war, but its withdrawal threatens to plunge Afghanistan back into repressive, bloody violence.

As Cold War tensions escalate, the US secretly enters the fight against North Vietnam, while widespread protests spark intense unrest in South Vietnam.