The Piccadilly Line is one of the major lines of the London Underground, serving the city of London and its surrounding areas. It is represented by the color dark blue on the Tube map and runs from Heathrow Airport in the west to Cockfosters in the north. The line has 53 stations and connects key locations, including Piccadilly Circus, Leicester Square, and Covent Garden. Opened in 1906, the Piccadilly Line has undergone several extensions and upgrades over the years. It is known for its deep-level tunnels and is one of the busiest lines in the network, providing essential transport for both commuters and tourists visiting London.