The Paris Métro or Métropolitain (French: Métro de Paris) is a rapid transit system in the Paris Metropolitan Area. A symbol of the city, it is noted for its density within the city limits and its uniform architecture, influenced by Art Nouveau. It is mostly underground and 214 kilometres (133 mi) long. It has 303 stations, of which 62 have transfers to another line. There are 16 lines, numbered 1 to 14 with two minor lines, 3bis and 7bis. Lines are identified on maps by number and colour, and direction of travel is indicated by the terminus.
It is the second-busiest metro in Europe, after Moscow. It carried 1.524 billion passengers in 2011, (up from 1.506 billion in 2010), 4.175 million passengers a day. It is one of the densest metro systems in the world, with 245 stations within the 86.9 km2 (34 sq mi) of the city of Paris. Châtelet – Les Halles, with 5 Métro lines and three RER commuter rail lines, is the world's largest metro (subway) station.