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.

The 1948 Summer Olympics were an international multi-sport event held from 29 July to 14 August 1948 in London, United Kingdom. Following a twelve-year hiatus caused by the outbreak of World War II, these were the first Summer Olympics held since the 1936 Games in Berlin. The 1940 Olympic Games had been scheduled for Tokyo and then for Helsinki, while the 1944 Olympic Games had been provisionally planned for London. This was the second time London hosted the Olympic Games, having previously hosted them in 1908, forty years earlier. The Olympics would return again to London 64 years later in 2012, making London the first city to host the games thrice, and the only such city until Paris and Los Angeles host their third games in 2024 and 2028, respectively. The 1948 Olympic Games were also the first of two summer Games held under the IOC presidency of Sigfrid Edström.