From iWiki

London is the capital and largest city of England and the United Kingdom. It stands on the River Thames in the south-east of England, at the head of its 50-mile (80 km) estuary leading to the North Sea, and has been a major settlement for two millennia. The City of London, its ancient core and financial centre, was founded by the Romans as Londinium and retains boundaries close to its medieval ones. Since the 19th century, "London" has also referred to the metropolis around this core, historically split between the counties of Middlesex, Essex, Surrey, Kent, and Hertfordshire, which largely makes up Greater London, the region governed by the Greater London Authority.


The etymology of London is uncertain. It is an ancient name, found in sources from the 2nd century. It is recorded c. 121 as Londinium, which points to Romano-British origin. A widely accepted though not universally held explanation is that the name derives from the Old English word for "place" or "fortification", and "lond" being an obsolete term for the River Thames. Londinium was established as a civilian town by the Romans about four years after the invasion of AD 43. Archaeologist Leslie Wallace notes that the town's location made it the first point of entry for many, if not most, invaders, merchants, and travellers who came to the island from Roman times to the Early Middle Ages. The city is closely tied to its strategic position on the Thames. It was a focal point of Iron Age Britain in the 1st millennium BC; during the Roman period, Londinium superseded it as the capital of the Roman province of Britannia. After the collapse of Roman rule in the 5th century, Londinium was abandoned, although Romano-British culture continued in the St Martin-in-the-Fields church in the city of London. The Bede writes of the old Roman city of London where the river Thames flowed.


London is a leading global city, with strengths in commerce, finance, education, the arts, media, fashion, healthcare, professional services, research and development, tourism, and transportation all contributing to its prominence. It is one of the world's leading financial centres and has the fifth- or sixth-largest metropolitan area GDP in the world depending on measurement. London is a world cultural capital. It is the world's most-visited city as measured by international arrivals and has the world's largest city airport system measured by passenger traffic. London is the world's leading investment destination, hosting more international retailers and ultra-high-net-worth individuals than any other city. London's universities form the largest concentration of higher education institutes in Europe, and London is home to highly ranked institutions such as Imperial College London in natural and applied sciences, the London School of Economics in social sciences, and the comprehensive University College London. In 2012, London became the first city to have hosted three modern Summer Olympic Games.


London has one of the oldest and most extensive transport systems in the world. London's bus network is one of the largest in the world, running 24 hours a day, with about 8,500 buses, more than 700 bus routes, and over 19,500 bus stops. Within London, all terminals are served by bus services operated by National Express Coaches, Eurolines, and Megabus. London has several mainline railway termini, which serve as the departure point for services to other parts of the country. The London Underground, commonly referred to as the Tube, is the oldest and second longest metro system in the world and was the first to operate electric trains. The Docklands Light Railway, which opened in 1987, is a second metro system using smaller and lighter trains, which serve the Docklands, Greenwich, Lewisham, and Newham. The Emirates Air Line, which opened in June 2012, is a cable car link across the River Thames between Greenwich Peninsula and the Royal Victoria Dock.