London is the capital of both England and the United Kingdom. It has been an influential city for two millennia, and its history goes back to its founding by the Romans, then named Londinium. London's core, the ancient City of London, still retains its limited medieval boundaries. However, since at least the nineteenth century, the name "London" has also referred to the whole metropolis that has developed around it. Today, the bulk of this conurbation forms the London region and the Greater London administrative area, with its own elected mayor and assembly.
London is a prominent global city and one of the world's largest financial centres. Central London is home to the headquarters of more than half of the UK's top 100 listed companies (the FTSE 100) and more than 100 of Europe's 500 largest. London's influence in politics, education, entertainment, media, fashion, the arts and culture in general contributes to its global position. It is a major tourist destination for both domestic and overseas visitors. London hosted the 1908 and 1948 Summer Olympics and will host the 2012 Summer Olympics.
London contains four World Heritage Sites: the Tower of London; the historic settlement of Greenwich; the Royal Botanic Gardens, Kew; and the site comprising the Palace of Westminster, Westminster Abbey and St. Margaret's Church.
London has a wide range of peoples, cultures, and religions, and more than 300 languages are spoken within its boundaries. In July 2007, it had an official population of 7,556,900 within the boundaries of Greater London, making it the most populous municipality in the European Union. The Greater London Urban Area has a population of 8,278,251. while the metropolitan area has an estimated total population of between 12 million and 14 million. The public transport network, administered by Transport for London, is the most extensive in the world, London Heathrow Airport is the world's busiest airport by number of international passengers and the airspace is the busiest of any urban centre in the world.London was named by New York Magazine as the capital of the world for the 21st century.
London can be geographically defined in a number of ways; the situation was once open to periodic legal debate. At London's core is the small, ancient City of London which is commonly known as 'the City' or 'the Square Mile'. London's metropolitan area grew considerably during the Victorian era and again during the Interwar period, but expansion halted in the 1940s because of World War II and Green Belt legislation, and the area has been largely static since. The London region of England, also commonly known as Greater London, is the area administered by the Greater London Authority.
Forty percent of Greater London is covered by the London postal district, within which 'LONDON' forms part of the postal address. The London telephone area code covers a larger area, similar in size to Greater London, although some outer districts are omitted and some places just outside are included. The area within the orbital M25 motorway is sometimes used to define the "London area" and the Greater London boundary has been aligned to it in places. Greater London is split for some purposes into Inner London and Outer London. Informally, the city is split into North, South, East, West and often also Central London.
The Metropolitan Police District, city-wide local government area and London transport area have varied over time, but broadly coincide with the Greater London boundary. The Romans may have marked the centre of Londinium with the London Stone, still visible on Cannon Street. Trafalgar Square has also become a point for celebrations and protests.
Within London, both the City of London and the City of Westminster have City status and both the City of London and the remainder of Greater London are the ceremonial counties. The current area of Greater London was historically part of the counties of Middlesex, Kent, Surrey, Essex and Hertfordshire. Unlike most capital cities, London's status as the capital of the UK has never been granted or confirmed officially — by statute or in written form. Its position as the capital has formed through constitutional convention, making its position as de facto capital a part of the UK's unwritten constitution. The capital of England was moved to London from Winchester as the Palace of Westminster developed in the 12th and 13th centuries to become the permanent location of the royal court, and thus the political capital of the nation. According to the Collins English Dictionary definition of 'the seat of government,' London is not the capital of England, as England does not have its own government. However according to the Oxford English Reference dictionary definition of 'the most important town...' and many other authorities, London is the capital of England.
Greater London covers an area of 607 square miles (1,570 km2). Its primary geographical feature is the Thames, a navigable river which crosses the city from the south-west to the east. The Thames Valley is a floodplain surrounded by gently rolling hills including Parliament Hill, Addington Hills, and Primrose Hill. The Thames was once a much broader, shallower river with extensive marshlands; at high tide, its shores reached five times their present width. Since the Victorian era it has been extensively embanked, and many of its London tributaries now flow underground. The Thames is a tidal river, and London is vulnerable to flooding. The threat has increased over time due to a slow but continuous rise in high water level by the slow 'tilting' of Britain caused by post-glacial rebound. In 1974, a decade of work began on the construction of the Thames Barrier across the Thames at Woolwich to deal with this threat. While the barrier is expected to function as designed until roughly 2030, concepts for its future enlargement or redesign are already being discussed.
London's vast urban area is often described using a set of district names (e.g. Bloomsbury, Knightsbridge, Mayfair, Whitechapel, Fitzrovia). These are either informal designations, or reflect the names of superseded villages, parishes and city wards. Such names have remained in use through tradition, each referring to a local area with its own distinctive character, but often with no modern official boundaries. However, since 1965 Greater London has been divided into 32 London boroughs in addition to the ancient City of London.
The City of London is one of the world's three largest financial centres (alongside New York and Tokyo) with a dominant role in several international financial markets, including cross-border bank lending, international bond issuance and trading, foreign-exchange trading over-the-counter derivatives, fund management and foreign equities trading. It also has the world's largest insurance market, the leading exchange for dealing in non-precious metals, the largest spot gold and gold lending markets, the largest ship broking market, and more foreign banks and investment houses than any other centre. The City has its own governance and boundaries, giving it a status as the only completely autonomous local authority in London. London's new financial and commercial hub is the Docklands area to the east of the City, dominated by the Canary Wharf complex. Other businesses locate in the City of Westminster, the home of the UK's national government and the well-known Westminster Abbey.
The West End is London's main entertainment and shopping district, with locations such as Oxford Street, Leicester Square, Covent Garden and Piccadilly Circus acting as tourist magnets. The West London area is known for fashionable and expensive residential areas such as Notting Hill, Knightsbridge and Chelsea — where properties can sell for tens of millions of pounds. The average price for all properties in the Royal Borough of Kensington and Chelsea is £894,000 with similar average outlay in most of Central London.
The eastern region of London contains the East End and East London. The East End is the area closest to the original Port of London, known for its high immigrant population, as well as for being one of the poorest areas in London. The surrounding East London area saw much of London's early industrial development; now, brownfield sites throughout the area are being redeveloped as part of the Thames Gateway including the London Riverside and Lower Lea Valley, which is being developed into the Olympic Park for the 2012 Olympics.