London
London is the capital and largest city of England and the United Kingdom, with a population of around 8.8 million.
It stands on the River Thames in south-east England at the head of a 50-mile (80 km) estuary down to the North Sea and has been a major settlement for nearly two millennia.

The City of London, its ancient core and financial centre, was founded by the Romans as Londinium and retains its medieval boundaries.
Despite the evidence of scattered Brythonic settlements in the area, the first major settlement was founded by the Romans around 47 AD, about four years after their invasion of 43 AD.
This only lasted until about 61 AD, when the Iceni tribe led by Queen Boudica stormed it and burnt it to the ground.
The next planned incarnation of Londinium prospered, superseding Colchester as the principal city of the Roman province of Britannia in 100. At its height in the 2nd century, Roman London had a population of about 60,000.

The local authorities are the councils of the 32 London boroughs and the City of London Corporation.They are responsible for most local services, such as local planning, schools, libraries, leisure and recreation, social services, local roads and refuse collection.
Certain functions, such as waste management, are provided through joint arrangements.

Underground and DLR
Opened in 1863, the London Underground, commonly referred to as the Tube or just the Underground, is the oldest and third longest metro system in the world.
The system serves 272 stations, and was formed from several private companies, including the world's first underground electric line, the City and South London Railway, which opened in 1890.

Over four million journeys are made every day on the Underground network, over 1 billion each year.
The Docklands Light Railway (DLR), which opened in 1987, is a second, more local metro system using smaller and lighter tram-type vehicles that serve the Docklands, Greenwich and Lewisham.

https://tfl.gov.uk/maps/track/tube