Line 10 of the Beijing Subway is the second loop line in Beijing's rapid transit network as well as the longest and most widely used line. The line is 57.1 km in length and runs entirely underground through Haidian, Chaoyang and Fengtai Districts, either directly underneath or just beyond the 3rd Ring Road. The Line 10 loop is situated between two to six kilometers outside of the Line 2 loop, which circumnavigates Beijing's old city. Every subway line through the city centre intersects with Line 10, which has 24 (currently 14 available) transfer stations along route, and 45 stations in all. Line 10's color is  Capri.