This Wednesday, 9th January, marked 150 years since the world’s first underground line opened – the London Metropolitan Railway between Paddington Station and Farringdon Street, stretching just under four miles. 
Steam trains chugged between Paddington and Farringdon Street on what is now the Circle line, carrying an average of 26,500 passengers a day during its first three months.
Today the network covers 402km of track, serves 270 stations, runs across 11 lines, and carries around 3.5 million passengers a day, or 1.2 billion passengers per year.
The London Transport Museum is celebrating London Underground artwork over the decades, in its Poster Art 150 exhibition running from February until October.
The exhibition showcases 150 of the best designs chosen by an independent panel, and the museum is inviting visitors to vote for their favourite poster, which will be unveiled at the end of the exhibition.
