On July 23, 1966, England and Argentina met in the quarter-finals of the World Cup at Wembley Stadium. It was a bad-tempered match from the start, but what happened in the 35th minute would change the sport forever. German referee Rudolf Kreitlein sent off Argentine captain Antonio Rattín. The problem was that Kreitlein didn't speak Spanish, and Rattín didn't speak German or English. The official reason given for the sending off was "violence of the tongue." Some accounts suggest it may have been nothing more than a dirty look. Rattín refused to leave. For nearly ten minutes, the match was held up as Rattín argued, teammates swarmed the referee, and FIFA officials tried to intervene. Ken Aston, the head of the tournament's referees committee, physically waded in to try to calm the situation. Eventually, police were brought onto the pitch to escort Rattín off. He didn't go quietly. As a final act of defiance, he sat down on the red carpet reserved exclusively for the Queen, and as he was finally marched away, he wrinkled an English pennant in his hands. England won the match 1-0 and went on to win the tournament. But the real legacy of the day was born on the drive home. Ken Aston, still turning the chaos over in his mind, stopped at a traffic light on Kensington High Street. He stared at the lights changing from green to yellow to red, and the idea hit him. Colors that every person on earth already understood, regardless of language. Yellow: take it easy. Red: you're off. The yellow and red card system was formally introduced at the 1970 World Cup in Mexico. It has been used in every World Cup since, and in virtually every professional football competition on the planet.

On July 23, 1966, England and Argentina met in the quarter-finals of the World Cup at Wembley Stadium. It was a bad-tempered match from the start, but what happened in the 35th minute would change the sport forever. German referee Rudolf Kreitlein sent off Argentine captain Antonio Rattín. The problem was that Kreitlein didn't speak Spanish, and Rattín didn't speak German or English. The official reason given for the sending off was "violence of the tongue." Some accounts suggest it may have been nothing more than a dirty look. Rattín refused to leave. For nearly ten minutes, the match was held up as Rattín argued, teammates swarmed the referee, and FIFA officials tried to intervene. Ken Aston, the head of the tournament's referees committee, physically waded in to try to calm the situation. Eventually, police were brought onto the pitch to escort Rattín off. He didn't go quietly. As a final act of defiance, he sat down on the red carpet reserved exclusively for the Queen, and as he was finally marched away, he wrinkled an English pennant in his hands. England won the match 1-0 and went on to win the tournament. But the real legacy of the day was born on the drive home. Ken Aston, still turning the chaos over in his mind, stopped at a traffic light on Kensington High Street. He stared at the lights changing from green to yellow to red, and the idea hit him. Colors that every person on earth already understood, regardless of language. Yellow: take it easy. Red: you're off. The yellow and red card system was formally introduced at the 1970 World Cup in Mexico. It has been used in every World Cup since, and in virtually every professional football competition on the planet.