Transporting 5 million passengers daily, the metro, or STC (Collective Transportation System), is one of the world's best, busiest, and cheapest transportation systems -- a ride costs 2 pesos (about 20). The clean marble-and-onyx stations are brightly lighted, and modern French-designed trains run quietly on rubber tires. Some stations, such as Insurgentes, are shopping centers. Even if you don't take a ride, visit the Zócalo station, which has large models of central Mexico City during three historic periods. Many stations have temporary cultural displays, from archaeological treasures to contemporary art; the Pino Suárez station has a small Aztec pyramid inside, a surprise discovery during construction.
There are 11 intersecting metro lines covering more than 200 km (124 mi). Segments of Lines 1 and 2 cover most points of interest to tourists, including Zona Rosa, Bellas Artes, and Centro Histórico. At the southern edge of the city, the Tasqueña station (Line 2) connects with an electric train called the tren ligero ("light" train), which continues south to Xochimilco. To the southeast, the tren ligero from the Pantitlán station (Lines 1, 5, and 9) heads east to Chalco in the state of México. The various lines also serve all four bus stations and the airport; however, only light baggage is allowed on board during rush hours. User-friendly color-coded maps are sometimes available free at metro-station information desks (if there's an attendant) and at Mexico City tourism offices; color-keyed signs and maps are posted all around.
Trains run frequently (about two minutes apart) and are least crowded from 10 to 4 and at night. To reduce incidences of harassment during crowded rush hours, and on crowded lines, regulations may require men to ride in separate cars from women and children. The cars for women and children are marked "exclusivo para mujeres y niños."
The metro is generally safe, but be careful of pickpockets. Hold on to your belongings on crowded trains, as some thieves will pretend to bump into you (or even pitch dramatically into you) as a means of distraction. Hours vary somewhat according to the line, but service is essentially weekdays 5 AM-midnight, Saturday 6 AM-midnight, Sunday and holidays 7 AM-midnight. Late at night it's still best to call a radio taxi or take a sitio, mostly because many of the neighborhoods surrounding metro stations are not safe at night.