According to the BBC:
A senior Olympic figure has told the BBC that London only won the 2012 Olympics because of a misplaced vote.
Alex Gilady claims the mistake happened when a vote was cast for Paris instead of the intended recipient, Madrid.
Had the vote gone to Madrid, claims Gilady, they would have finished level with Paris on 32 votes apiece in the penultimate round, behind London.
Gilady suggests Madrid would have won a head-to-head vote with Paris and gone on to beat London in the final round.
Either way, Paris would have lost