1. New York
The New York City Subway is a rapid transit system owned by the City of New York and leased to the New York City Transit Authority. The NYCTA is a subsidiary of Metropolitan Transportation Authority. From 28 stations, when it was founded in October, 1904, it has grown to 462 stations. The subway carries 4.9 million people daily. It is one of the most extensive public transportation systems in the world, with 369 km of rail route. The subway is also among the few rapid transit systems in the world to run 24 hours a day and 365 days a year.
The London Underground, usually referred to as the Tube, is Europe’s largest metro subway system and also the world’s oldest. Inaugurated in 1863, today it has 268 stations and covers 405 km of rail tracks. It transports over 976 million people yearly. The Underground serves a large part of Greater London and neighbouring areas of Essex, Hertfordshire and Buckinghamshire in England.
The Paris subway system is the second oldest in the world and transports roughly 1.5 million people daily at modest fares. The subway system runs over 214 km and stops at 380 stations. The network is so extensive that almost every building in Paris is within 500 meters of a subway station. Many of these stations are famous for their architecture, representing the Art Nouveau style.
The Moscow subway system caters to 3.2 billion riders travelling annually on 12 subway lines to 172 stations. The Moscow Metro covers approximately 290 km. On an average weekday, the subway itself carries about 8.2 million passengers. Each subway line is identified by an alphanumeric index (usually consisting of just a number), a name, and a color. The voice announcement systems refer to lines by name, while in colloquial usage they are mostly referred to by color. While most of the Moscow trains run underground, some lines cross bridges overlooking the Moskva and the Yauza Rivers.
The Montreal Metro is a rubber-tired metro system, and the main form of public transportation in the city of Montreal, Quebec, Canada. Inaugurated in 1966, it is not too extensive — about 60 km, reaching 68 stations on four lines — but is a very modern system that was inspired by the Paris Metro. It caters to 835,000 people daily. The Metro is operated by the Societe de Transport de Montreal
The Madrid Metro is the second largest underground system in Europe and the sixth largest in the world. The first line of the Madrid metro opened on October 17, 1919, under the direction of the Compania de Metro Alfonso XIII, with 8 stations and a 3.5-km track. This metro network now has 231 stations on 12 lines. It has 227 km of track and an additional 44 km of track is expected to be completed by the end of this year. The Madrid Metro is one of the densest metro networks in the world.