Sport and politics should never be mixed.
1968: Tommy Smith and John Carlos protest during the medal ceremony while the US National Anthem plays. They were protesting against poverty and the treatment of black people.
1967: Muhammad Ali is prohibited from defending his boxing titles after refusing to go and fight in Vietnam.
1906: Peter O'Conner climbs the flagpole at the Intercalated Games and replaces the Union Jack with this flag (it says 'Ireland Forever'). Irish athletes back then had their medals credited to Britain, the USA or Canada.
1969: After being racially abused against the BYU team in 1968, the black players on the Wyoming University football team wanted to have a silent protest when the two teams played each other the next year. They asked their coach if they could wear black armbands in protest. They were all kicked off the team. This led to massive protests around the country.
1976: 28 African countries boycott the Olympics as a protest against New Zealand being allowed to compete in the games after sending their Rugby team to play in Apartheid South Africa. This was just after the South African government massacred 350 anti-apartheid protesters.