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.

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

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

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.