The Paris Métro, operated by the Régie Autonome des Transports Parisiens (RATP), is a rapid transit system in the Paris metropolitan area, France. Inaugurated on July 19, 1900, the Paris Métro is one of the oldest metro systems in the world, and its lines The complex network plays an integral role in the daily lives of Parisians and the millions of visitors who discover the City of Light. The system is 226.9 kilometers (141.0 mi) long, mostly underground. It has 308 stations of which 64 have transfers between lines. It has 16 lines, numbered 1 to 14, with two lines, 3bis and 7bis, so named because they began as branches of Line 3 and Line 7, respectively. Line 1, Line 4 and Line 14 are automated. Lines on maps are identified by number and colour, with the direction of travel indicated by the terminus.