The 2012 Summer Olympics, officially the Games of the XXX Olympiad and also known as London 2012, were an international multi-sport event held from 27 July to 12 August 2012 in London, England. Some events were held at stadiums in Glasgow, Scotland and Cardiff, Wales. The first event, the group stage in women's football, began on 25 July at the Millennium Stadium in Cardiff, followed by the opening ceremony on 27 July. There were 10,518 athletes from 206 National Olympic Committees (NOCs) who participated in the 2012 Olympics.
Following a bid headed by former Olympic champion Sebastian Coe and the then-London mayor Ken Livingstone, London was selected as the host city at the 117th IOC Session in Singapore on 6 July 2005, defeating bids from Moscow, New York City, Madrid, and Paris. London became the first city to host the modern Olympics three times, having previously hosted the Summer Games in 1908 and 1948. Construction for the Games involved considerable redevelopment, with an emphasis on sustainability. The main focus was a new 200-hectare (490-acre) Olympic Park, constructed on a former industrial site in Stratford, East London. The Games also used venues that already existed before the bid.