On this day: October 21

Double Agent Exposed: Cold War Spy Scandal Surfaces

On October 21, 1964, the revelation that a long-trusted intelligence officer had been operating as a double agent ignited a major Cold War scandal, prompting investigations, political fallout, and questions about intelligence countermeasures.

Pan Am Flight 103 Bombing Investigation Widens Across Borders

On October 21, 1988, Pan Am Flight 103 exploded over Lockerbie, Scotland; subsequent investigations grew into a complex international probe involving forensic teams, intelligence agencies, and legal actions spanning the U.S., U.K., and several countries.

Chicago Police Clash With Antiwar Demonstrators at October 1967 Rallies

On October 21, 1967, thousands of anti–Vietnam War demonstrators in Chicago faced mass arrests and force by police following clashes near the Civic Center and Loop; the confrontations reflected mounting national tensions over the war and public protest tactics.

NASA Loses Contact with Mars Observer Spacecraft

On October 21, 1993, NASA announced it had lost contact with the Mars Observer spacecraft shortly before its scheduled arrival at Mars orbit, leaving the mission's fate uncertain and prompting an investigation into the cause.

Mass Antiwar Demonstrations Bring Washington to a Standstill on October 21, 1967

On October 21, 1967, hundreds of thousands of protesters converged on Washington, D.C., staging one of the largest anti-Vietnam War demonstrations in U.S. history that disrupted traffic, closed government buildings and filled the National Mall with activists demanding an end to the conflict.