line L4 of Barcelona Metro Italian Schema della linea L4 della Metropolitana di Barcellona Spanish Termómetro de la línea L4 del Metro de Barcelona Catalan
DescriptionL4 metro de Barcelona (Pla 66 i 74).svg English: The L4 of the metro de Barcelona in the plannings of 1966 (black, circle line) and 1974 (grey)