The Piccadilly line is coloured dark blue on the Tube map. It is the fourth busiest line on the Underground. Classed as a deep-level line, th majority of its stations are actually above ground, of the 53 stations only 25 are below ground.
It serves many of the top tourist attractions including Harrods (Knightsbridge), Hyde Park Corner, Buckingham Palace (within walking distance from Green Park), Piccadilly Circus (after which the line is named), Leicester Square and Covent Garden, as well as Heathrow Airport.
- Shortest distance between stations is Leicester Square to Covent Garden at 0.3km and about 35 seconds from start to stop.
- A fragrance known as Madeleine was trialled at St. James Park, Euston, and Piccadilly Circus stations in 2001, to make the Tube more pleasant. It was stopped within days after complaints from people saying they felt ill.