London is the largest urban area and the capital of England and United Kingdom.An important settlement for two millennia, London's history goes back to its founding by the Romans.Since its settlement, London has been part of many important movements and phenomena throughout history, such as the English Renaissance, the Industrial Revolution, and the Gothic Revival.The city's core, the ancient City of London, still retains its limited medieval boundaries; but since at least the 19th century the name "London" has also referred to the whole metropolis which has developed around it.Today the bulk of this conurbation forms the London region of England and the Greater London administrative area,with its own elected mayor and assembly. London is one of the world's leading business, financial, and cultural centres,and its influence in politics, education, entertainment, media, fashion and the arts all contribute to its status as a major global city.London boasts four World Heritage Sites: The Palace of Westminster, Westminster Abbey and St. Margaret's Church; the Tower of London; the historic settlement of Greenwich; and the Royal Botanic Gardens, Kew.The city is one of the most popular tourist destinations in the world, and its popularity has increased over the years due to economic growth. London's diverse population draws from a wide range of peoples, cultures, and religions, and over 300 languages are spoken within the city.As of 2006, it has an official population of 7,512,400 within the boundaries of Greater London and is the most populous municipality in the European Union.As of 2001, the Greater London Urban Area has a population of 8,278,251 and the metropolitan area is estimated to have a total population of between 12 and 14 million.London will be hosting the 2012 Summer Olympics.

Greater London covers an area of 609 square miles (1,579 km²), making it the 37th largest urban area in the world.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 such as Parliament Hill, Addington Hills, and Primrose Hill. These hills presented no significant obstacle to the growth of London from its origins as a port on the north side of the river, and therefore London is roughly circular. Many of the highest points in London are located in the suburbs or on the boundaries with adjacent counties. 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 (up in the north and down in the south) 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 has a temperate marine climate, like much of the British Isles, so the city rarely sees extremely high or low temperatures (such as heat wave of 2003 and the cold wave of 2006). Summers are warm with average high temperatures of 23°C (73°F) and lows of 14°C (57°F), however, temperatures could exceed 25°C (77°F) on many days. Winters in London are chilly, but rarely below freezing with temperatures around 2 - 8°C (36 - 46°F), while spring has mild days and cool evenings. London has regular but generally light precipitation throughout the year, with average precipitation of 583.6 mm (22.98 in) every year. Snow is relatively uncommon, particularly because heat from the urban area can make London up to 5 °C (9 °F) hotter than the surrounding areas in winter. Light snowfall, however, is sometimes seen a few times a year, although it is not uncommon to have no snow during the colder months.