The Athens Transit System consists of a large bus fleet, a trolleybus fleet that mainly serves the downtown area. The city’s Metro, a tram line connecting the southern suburbs to the city centre, and the Athens Suburban Railway service..
While its main purpose is transport, the stations house Greek artifacts found during construction of the system. The two lines (red and blue) were constructed largely during the 1990s and the initial sections opened in January 2000. The lines run entirely underground. The metro network operates a fleet of 42 trains consisting of 252 cars with a daily occupancy of 550,000 passengers. The Blue Line runs from the western suburbs through the central Monastiraki and Syntagma stations to the northeastern suburbs and covers a distance of 16 km (10 mi), It then ascends to ground level and reaches Eleftherios Venizelos International Airport using the Suburban Railway infrastructure and extending its distance to 39 km (24 mi). The Red Line runs from Aghios Antonios to Aghios Dimitrios and covers a distance of 11.6 km (7 mi). Extensions to both these lines are under construction, most notably westwards to Piraeus and southwards to the Old Hellinikon Airport East Terminal (the future Metropolitan Park). The spring 2007 extension from Monastiraki, westwards to Egaleo, connected some of the main night life hubs of the city of Athens, namely Gazi (Kerameikos station), Psirri (Monastiraki station) and the city centre (Syntagma station).
This network runs the original metro line from Piraeus to Kifisia and serves 22 stations, with a network length of 25.6 km (15.9 mi), a fleet of 44 trains and 243 cars and a daily occupancy rate of 600,000 passengers. The historic Green Line is set to be extended to Agios Stefanos, a suburb located 23 km (14 mi) to the north of the city centre, reaching to 36 km (22 mi) in length.