The meaning of the name "London" is unclear, and has been the subject of spirited debate. The first major settlement established there was in 43 AD, by the Romans. It was destroyed around 61 by Queen Boudica, who razed it to the ground. The city, then called Londinium, was rebuilt as the Roman capital of Britannia in about 100, and had a population of about 60,000 during the 2nd century. In the 5th century Roman rule essentially ended. An Anglo-Saxon settlement was established about 2 kilometres up the River Thames, called Lundenwic, during the 7th century. Viking attacks began in the 9th century, and continued until the city was captured in 886 by Alfred the Great, who made peace with Guthrum, the Danish leader. Lundenwic then became Ealdwic, later anglicized to Aldwych. When England was unified in the 10th century, London was the largest city and most important trading area. In the 11th century Westminster, which was slightly upstream from London, was re-founded and became a royal residence. It became the seat of the newly stationary government during the 12th century. However, London remained the largest city, and was the economic centre. By 1300 it had a population of about 100,000. However, in the mid-14th century the Black Death moved into London from mainland Europe, carried by the bustling trade that fed the city. About a third of the population of London was lost to the plague. Lesser outbreaks occurred throughout the late 14th and early 15th century.
In the late 15th century the Tudor period began, and marked a slow shift towards Protestantism. The Catholic church began to lose control over much of London, which passed into private hands. The population began to recover from the plague, hitting about 50,000 in 1530. Mercantilism was on the rise; the British East India Company was founded in 1600, and trade to the New World began. Most of this new trade was run through London's port, which was rapidly becoming the major North Sea port. London remained overcrowded and compact, however, and was wracked by disease in the 17th century, ending in a resurgence of the Black Death between 1665 and 1666, called the Great Plague of London, which killed a fifth of the population, about 100,000 people. Also in 1666, London was struck by the Great Fire of London, which destroyed a great deal of wooden buildings and took 10 years to repair fully. The 18th century saw an addition of new areas to the rapidly expanding London, and new bridges were built to cross the Thames and encouraged the development in the south of London. The Port of London also expanded to the east and downstream. As well, the 18th century saw a major increase in crime, followed by the establishment of the Bow Street Runners as the first professional police force in London. Literacy began to increase among the lower classes around this point, but there was still a great deal of stratification, and mortality rate for children under 5 hovered around 74%.
Starting in 1831, it was the world's largest city, and remained so until the mid-1920s. It remained immensely overcrowded, which led to continued outbreaks, such as the cholera epidemics of 1848 and 1866, which collectively claimed some 20,000 lives. London attracted a great deal of immigration, which swiftly created a poor underclass who gravitated to the poor regions of London, such as Whitechapel. To deal with the traffic congestion created by the growing population, the London Underground, the oldest metro system in the world, began operation in 1863. In 1889 the first city-wide elected body, the London County Council, replaced previous administrative bodies. During the Second World War, the Luftwaffe bombed London in The Blitz, bombing for 76 consecutive nights and killing some 30,000 Londoners. Large swathes of London were completely destroyed by the bombing. In 1948 London hosted the Summer Olympics, despite having barely recovered from the war.
From the 1950s onwards London saw immense immigration from Commonwealth countries, and London soon became one of the most diverse cities in Europe. 1952 also saw the Great Smog of 1952, which led to the passage of the Clean Air Act 1956 which finally put an end to the "pea-souper" fogs for which London was famous. During the 1960s the youth counterculture movement arose in London, most notably the Swinging London movement, which emphasized optimism and hedonism and was centred on Carnaby Street in the Soho district. London's political boundaries expanded in 1965, when the Greater London Council was created. Starting in the late 1960s, the Troubles in Northern Ireland spread over to London, which was the target of bombings at the hands of the Provisional IRA. In the 1970s London again became a countercultural centre as it saw the development of the punk movement. In 1981 the Brixton Riot drew attention to the racial tensions and inequality in London. By the 1980s the population of London had declined significantly, with two million less people than there had been before the Blitz. In 1986 the Greater London Council was dissolved, leaving London with no centralized government. In 2000 a centralized government was reinstated in the form of the Greater London Authority. On July 7th, 2005 several London Underground trains were struck in a series of suicide attacks orchestrated by terrorist organization al-Qaeda. In early August of 2011 London was the epicentre of several days of rioting and looting which later spread to other areas of England. In 2012 London played host to the Summer Olympics.
London currently has a population of just over 7 million people. A majority of these people are white, about 69%. The second most common group is those of South Asian descent, about 13%, most of them from India and less from Pakistan and Bangladesh. 10% of the population is black, 3.5 are mixed race and 1.5 are Chinese. A majority of those living in London were born in the UK, while about 27% report being born outside of the UK. Over half of the population reports being Christian, and the next most common religion is "no religion", followed by "religion not stated", and Muslim. There are also smaller groups, with less than 5% of the population each, who report being Hindu, Jewish, Sikh, Buddhist, Pagan or Other.
London is located in the south of England. The city covers an area of just under 1,600 square kilometres. It straddles the River Thames, which divides the city into North and South; it has been heavily embanked to prevent flooding, but the river is tidal, fed by the North Sea, and London is still vulnerable to flooding. London is divided into five sub-regions that are further divided into 32 boroughs, which are themselves divided into over four hundred districts. These districts are usually informal designations that indicate smaller towns that were absorbed as the city expanded, or parishes or former boroughs of the city. The core of the city, the City of London, retains for the most part its mediaeval boundaries, and the remaining boroughs are situated around it. The city can also be divided into Inner and Outer London. The West End of London is the expensive entertainment and shopping district, while the East End was historically the poor region, and is currently being redeveloped.