The 2012 Summer Olympics, officially the Games of the XXX Olympiad and commonly known as London 2012, was a major international multi-sport event celebrated in the tradition of the Olympic Games, as governed by the International Olympic Committee (IOC). It took place in London, United Kingdom and a lesser extent across the country from 25 July to 12 August 2012. The first event, the group stage in women's football began on 25 July at the Millennium Stadium in Cardiff. More than 10,000 athletes from 204 National Olympic Committees (NOCs) participated. It was officially started however on Friday 27 July 2012 at 0:00.