1968 Olympic Games (Mexico)
Controversy dogged the Mexico City Olympic Games from first to last. Even before the opening ceremony, a student riot in the city was brutally put down by the authorities, and the berets, black gloves and clenched-fist salutes of the American "Black Power" athletes severely embarrassed the US Olympic Association and led to some athletes being summarily expelled from the games.
Mexico City's altitude (about 7,000 feet) created a parallel controversy: would the thin air be dangerous for competitors in endurance sports? And would it distort performances in the explosive events?
The results gave the answers. Every running event under 800 metres (with the exception of David Hemery's world record victory for Britain in the 400 metres hurdles) was won by a black American sprinter in, or near, a world record time.