The Mexico City Metro () is a rapid transit system that serves the metropolitan area of Mexico City, including some municipalities in Mexico State. Operated by the Sistema de Transporte Colectivo (STC), it is the second largest metro system in North America after the New York City Subway. In 2019, the system served 1.655 billion passengers, the tenth highest ridership in the world. The inaugural STC Metro line was long, serving 16 stations, and opened to the public on 4 September 1969. The system has expanded since then in a series of fits and starts. , the system has 12 lines, serving 195 stations, and of route. Ten of the lines are rubber-tired. Instead of traditional steel wheels, they use pneumatic traction, which is quieter and rides smoother in Mexico City's unstable soils. The system survived the 1985 Mexico City earthquake. Of the STC Metro's 195 stations, 44 serve two or more lines (correspondencias or transfer stations). Many stations are named for historical figures, places, or events in Mexican history. It has 115 underground stations (the deepest of which are below street level); 54 surface stations and 26 elevated stations. All lines operate from 5 a.m. to midnight. At the end of 2007, the Federal District government announced the construction of the most recent STC Metro line, Line 12, which was built to run approximately towards the southeastern part of the city, connecting with Lines 7, 3, 2 and 8. This line opened on 30 October 2012. The Metro has figured in Mexico's cultural history, as the inspiration for a musical composition for strings, "Metro Chabacano" and Rodrigo "Rockdrigo" González's 1982 song, "Metro Balderas". It was also a filming location for the 1990 Hollywood movie Total Recall. Public intellectual Carlos Monsiváis has commented on the cultural importance of the Metro, "a space for collective expression, where diverse social sectors are compelled to mingle every day". History Concept of the Metro and early plans By the second half of the twentieth century, Mexico City had serious public transport issues, with congested main roads and highways, especially in the downtown zone, where 40 percent of the daily trips in the city were concentrated. 65 of the 91 lines of bus and electric transport served this area. With four thousand units in addition to 150,000 personal automobile peak hours, the average speed was less than walking pace. The principal promoter of the construction