Two African-American athletes sent shockwaves around the world from the Olympics in Mexico on this day in 1968, when they gave a raised-fist salute in support of human rights at the Men’s 200 metres medal ceremony.

Tommie Smith and John Carlos, respectively gold and bronze medallists in the race, stood with their heads bowed and a black-gloved hand raised as the American flag was hoisted and its national anthem played during the ceremony.

The men made their silent protest - shoeless and in black socks, while Smith wore a black scarf around his neck - against continuing racial discrimination of black people in the United States, and for human rights around the world.

Smith (centre) and Carlos (right) give the salute while Norman (front) wore the badge of the Olympic Project for Human Rights.

Both men – along with Australian silver medallist Peter Norman – wore badges of the Olympic Project for Human Rights (OPHR), an organisation which campaigned for an end to racism in the Olympics, and sport in general. They were booed by many in the crowd as they left the podium.

At a press conference, they explained that the scarf represented black pride, while their socks with no shoes reflected black poverty in the US. "Black America will understand what we did tonight," said Smith.

[Read more: August 3, 1936 - Jesse Owens wins 100m gold in front of Adolf Hitler at the Berlin Olympics]

Smith, a student at a Californian University who had broken the world record in winning the 200m gold, had told reporters earlier in the year that black US athletes were considering a total boycott of the 1968 Olympics.

He said: "It is very discouraging to be in a team with white athletes. On the track you are Tommie Smith, the fastest man in the world, but once you are in the dressing rooms you are nothing more than a dirty Negro."

The International Olympic Committee (IOC) condemned Smith and Carlos for what they called "a deliberate and violent breach of the fundamental principles of the Olympic spirit."  Two days later, the men were expelled from the US Olympic team and sent home.