In May 1960, with a Four Powers peace summit weeks away, an American U-2 spy plane piloted by Francis Gary Powers was shot down over the Soviet Union. This episode traces how that single flight and the cover-up that followed destroyed a rare window for arms reduction and accelerated the most dangerous phase of the Cold War. We start with Khrushchev's diplomatic trap and the American weather-plane lie.

We explain the physics of the U-2's coffin-corner flight at 70,000 feet, why it was believed untouchable, and how the new S-75 surface-to-air missile with a proximity fuse brought it down. We cover Powers's harrowing bailout, the friendly-fire death of a Soviet pilot caused by an IFF code failure on May Day, and Eisenhower's decision to own the espionage program rather than accept Khrushchev's offered scapegoat.

• Why Eisenhower autho ...