The Hammersmith & City line of the London Underground runs between Hammersmith and Barking. Coloured salmon pink on the tube map, it serves 29 stations in 15.8 miles (25.5 km). It is underground in the central section between Paddington and Bow Road; between Farringdon and Aldgate East it skirts the City of London, the capital's financial heart. The tunnels are just below the surface and are a similar size to those on British main lines.