London

London, the capital of England and the United Kingdom, is the country's largest city. In 2025, its population stood at 4 million, while the wider metropolitan area, the largest in Western Europe, held 15.4 million people. Situated in southeast England on the River Thames, the city sits at the head of a 50-mile tidal estuary that flows into the North Sea. For nearly two millennia, it has been a major settlement.

Its ancient core, the City of London, was established by the Romans as Londinium and still follows its medieval boundaries. To its west, the City of Westminster has housed the national government and parliament for centuries. During the 19th century, London expanded rapidly and became the world's largest city at that time. Since the 1800s, "London" has referred to the metropolis surrounding the City of London, historically divided among the counties of Middlesex, Essex, Surrey, Kent, and Hertfordshire.

Since 1965, it has largely consisted of the administrative area of Greater London, governed by 33 local authorities and the Greater London Authority.

As a major global city, London strongly influences world art, architecture, culture, cinema, entertainment, commerce, finance, education, healthcare, media, science, technology, tourism, transport, and communications. It boasts Europe's largest city economy and is a key global financial centre. The city hosts several leading academic institutions and Europe's highest concentration of higher education, with over 50 universities and colleges enrolling more than 500,000 students in 2023.

It is Europe's most-visited city and has the world's busiest city airport system. The London Underground is the oldest rapid transit system on the planet. London's cultural diversity spans over 300 languages. In 2025, Greater London's population of just over 9.8 million made it Europe's third-most-populous city, accounting for 13.1% of the UK's population and 15.5% of England's. The Greater London Built-up Area, with about 9.8 million inhabitants in 2011, is the fourth-most-populous in Europe.

The London metropolitan area, with roughly 15 million people in 2025, qualifies the city as a megacity and is the third-most-populous in Europe.

Notable landmarks include the Tower of London, Westminster Abbey, Buckingham Palace, the London Eye, Piccadilly Circus, St Paul's Cathedral, Tower Bridge, and Trafalgar Square. The city holds more museums, art galleries, libraries, and cultural venues than anywhere else in the UK, such as the British Museum, the National Gallery, the Natural History Museum, Tate Modern, the British Library, and numerous West End theatres. Major annual sporting events include the FA Cup Final at Wembley Stadium, the Wimbledon Tennis Championships, and the London Marathon. London became the first city to host three Summer Olympic Games, having done so in 1908, 1948, and 2012.

The name London is first recorded in the first century AD, usually in a Latinised form. Modern analysis of the name must account for the origins of different early forms found in Latin, Old English, and Welsh, considering sound changes over time in those languages. The name entered these languages from Common Brythonic, with the lost Celtic form most likely being something else. Until 1889, "London" officially referred only to the City of London; after that, it also denoted the County of London and later Greater London.

Evidence of prehistoric settlement includes Bronze Age bridge remains found in 1993 on the south Thames foreshore upstream from Vauxhall Bridge, with two timbers radiocarbon-dated to 1750–1285 BC. In 2010, foundations of a large timber structure from 4800–4500 BC were discovered on the same foreshore downstream from Vauxhall Bridge. Both sites are on the south bank, where the now-underground River Effra meets the Thames. The first major settlement, however, was founded by the Romans around AD 47, about four years after their invasion in AD 43. It lasted only until about AD 61, when the Iceni tribe led by Queen Boudica stormed and burned it. The next planned incarnation of Londinium thrived, replacing Colchester as the principal city of the Roman province of Britannia in AD 100. At its peak in the 2nd century, Roman London had roughly 60,000 inhabitants.

After Roman rule collapsed in the early 5th century, the walled city of Londinium was largely abandoned, though Roman civilisation continued around St Martin-in-the-Fields until about 450. From around 500, an Anglo-Saxon settlement called Lundenwic developed slightly west of the old Roman city. By about 680, the city had become a major port again, though evidence of large-scale production is scarce. Repeated Viking assaults from the 820s brought decline.

The Vikings imposed Danelaw over much of eastern and northern England from 886; the Anglo-Saxon Chronicle records that Alfred "refounded" London that year, which meant abandoning Lundenwic and reviving life and trade within the old Roman walls. London then grew slowly until a dramatic increase around 950. By the 11th century, it was clearly England's largest town. Westminster Abbey, rebuilt in Romanesque style by King Edward the Confessor, was among Europe's grandest churches.

While Winchester had been the capital of Anglo-Saxon England, London from this time became the main forum for foreign traders and the base for defence in wartime. As historian Frank Stenton noted, "It had the resources, and it was rapidly developing the dignity and the political self-consciousness appropriate to a national capital."