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, United Kingdom. The first event, the group stage in women's football, began on 25 July at the Millennium Stadium in Cardiff, Wales, 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.

London is the capital and largest city of both England and the United Kingdom, with a population of around 8.8 million, and its metropolitan area is the largest in Western Europe, with a population of 14.9 million. It stands on the River Thames in south-east England at the head of a 50-mile (80 km) estuary down to the North Sea and has been a major settlement for nearly two millennia. The City of London, its ancient core and financial centre, was founded by the Romans as Londinium and retains its medieval boundaries. The City of Westminster, to the west of the City of London, has for centuries hosted the national government and parliament. In the 19th century, London grew rapidly, becoming the world's largest city at the time, as it expanded and absorbed the neighbouring county of Middlesex, and parts of Surrey and Kent. In 1965 it was combined with parts of Essex and Hertfordshire to create the administrative area of Greater London, which is governed by 33 local authorities and the Greater London Authority.