Mayor of London Boris Johnson, right, shakes the hand of Mayor of Rio de Janeiro, Eduardo Paes, during a press conference in London to outline how London is working with the Brazilian city to ensure a smooth handover when the London 2012 Olympic Games come to an end over the up-coming weekend, in London Friday, Aug. 10, 2012.  Rio de Janeiro is to host the 2016 Olympic Games.(AP Photo/Sang Tan)

Photo by: Sang Tan

Mayor of London Boris Johnson, right, shakes the hand of Mayor of Rio de Janeiro, Eduardo Paes, during a press conference in London to outline how London is working with the Brazilian city to ensure a smooth handover when the London 2012 Olympic Games come to an end over the up-coming weekend, in London Friday, Aug. 10, 2012. Rio de Janeiro is to host the 2016 Olympic Games.(AP Photo/Sang Tan)