The second largest system in the U.S., Chicago's CTA makes getting around on public transit a cheap and easy option. The famous "L" trains are the system's defining feature. The first elevated trains began running in 1892 and have since shaped the evolution of the city as the train's multi-coloured network radiated out from the core. The "L" now services 144 stations 24-hours a day, each one the hub of a neighborhood. The fare is $2.25.