Based on the world record nomination from Europe Records Institute (EURI) and Decision No. WK/USA.INDIA/603/2020/No.59, World Records Union (WorldKings) officially declared London Underground as World’s first metro system.
The London Underground (also known simply as the Underground, or by its nickname the Tube) is a rapid transit system serving Greater London and some parts of the adjacent counties of Buckinghamshire, Essex and Hertfordshire in the United Kingdom.
London Underground has been owned and operated by Transport for London subsidiary London Underground Limited since 2007. Originally, tube lines were owned by various private companies until 1933 when the London Passenger Transport Board was introduced. Ownership of the London Underground was then passed to London Regional Transport in 1984.
Opened in January 1863, it is now part of the Circle, Hammersmith & City and Metropolitan lines; the first line to operate underground electric traction trains, the City & South London Railway in 1890, is now part of the Northern line.
The network has expanded to 11 lines, and in 2017/18 was used for 1.357 billion passenger journeys, making it the world's 12th busiest metro system. The 11 lines collectively handle up to 5 million passenger journeys a day.
It is also the world’s third longest metro system, the system has 270 stations and 250 miles (400 km) of track. Despite its name, only 45% of the system is underground in tunnels, with much of the network in the outer environs of London being on the surface. In addition, the Underground does not cover most southern parts of Greater London, and there are only 29 stations south of the River Thames.
According to en.wikipedia