surrounding the capital. London was bombed by the Germans during the First World War while

London was the world's largest city from about 1831 to 1925.[72] London's overcrowded conditions led to cholera epidemics,[73] claiming 14,000 lives in 1848, and 6,000 in 1866.[74] Rising traffic congestion led to the creation of the world's first local urban rail network. The Metropolitan Board of Works oversaw infrastructure expansion in the capital and some of the surrounding counties; it was abolished in 1889 when the London County Council was created out of those areas of the counties surrounding the capital. London was bombed by the Germans during the First World War while during the Second World War the Blitz and other bombing by the German Luftwaffe killed over 30,000 Londoners and destroyed large tracts of housing and other buildings across the city. Immediately after the war, the 1948 Summer Olympics were held at the original Wembley Stadium, at a time when London had barely recovered from the war.
In 1951, the Festival of Britain was held on the South Bank. The Great Smog of 1952 led to the Clean Air Act 1956, which ended the "pea soup fogs" for which London had been notorious. From the 1940s onwards, London became home to a large number of immigrants, largely from Commonwealth countries such as Jamaica, India, Bangladesh and Pakistan, making London one of the most diverse cities in Europe.
Primarily starting in the mid-1960s, London became a centre for the worldwide youth culture, exemplified by the Swinging London subculture associated with the King's Road, Chelsea and Carnaby Street. The role of trendsetter was revived during the punk era. In 1965 London's political boundaries were expanded to take into account the growth of the urban area and a new Greater London Council was created. During The Troubles in Northern Ireland, London was subjected to bombing attacks by the Provisional IRA. Racial inequality was highlighted by the 1981 Brixton riot. Greater London's population declined steadily in the decades after the Second World War, from an estimated peak of 8.6 million in 1939 to around 6.8 million in the 1980s. The principal ports for London moved downstream to Felixstowe and Tilbury, with the London Docklands area becoming a focus for regeneration as the Canary Wharf development. This was borne out of London's ever-increasing role as a major international financial centre during the 1980s.
The Thames Barrier was completed in the 1980s to protect London against tidal surges from the North Sea. The Greater London Council was abolished in 1986, which left London as the only large metropolis in the world without a central administration. In 2000, London-wide government was restored, with the creation of the Greater London Authority. To celebrate the start of the 21st century, the Millennium Dome, London Eye and Millennium Bridge were constructed. On 6 July 2005 London was awarded the 2012 Summer Olympics, making London the first city to stage the Olympic Games three times.