Underneath the busy streets of London, England, is a vast network of circular tunnels of the London Underground rapid transit system. Nicknamed "The Tube," it is the world's first subway, opening in 1863. The King's Cross-St Pancras station was one of the first and is still the busiest. The logo -- or 'roundel'-- is designed with a red circle to symbolize the city and a blue bar running through to represent the River Thames.

08.01.23