The Catania Metro (Italian: Metropolitana di Catania) is a classical metro system serving the city of Catania, Sicily, in southern Italy. It is the southernmost metro in Europe. The Catania Metro has been in operation since 27 June 1999, and consists of a single 3.84-kilometre (2.39 mi) line with six stations. The line is underground for approximately half of its length (between the stations of Borgo and Galatea). Service frequency is limited to once every 15 minutes because the line is single-track for half of its length (over the at-grade section between stations Galatea and Porto), hence trains operate as shuttles.