The Twin Scandal
Back in 1984, the summer games were held in LA. Puerto Rican track and field athlete, Madeline de Jesus, tweaked a muscle during the long jump. However her twin sister happened to be in town at the time and replaced her sister in the 4x400m relay. During the race the pair got away with it, however the coach soon realised what was going on and withdrew the team.
Black Power Salute
In 1968 the games were held in Mexico City amidst the American Civil Rights movement. Controversially after Tommie Smith and John Carlos took gold and bronze in the 200m run, the pair raised their gloved hands and did the black power salute, which at the time was associated with violence and extremism.