
There are around 160 metro systems in the world. The first metro system, the London Underground, was opened in 1863.
While Shanghai Metro is the longest system in passenger route length, the Tokyo Subway is the world's busiest in terms of passenger rides per year.
1. Tokyo Subway
(Tokyo Metro and Toei Subway only)
Passenger rides per year: 3.161 billion (2010)
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2. Moscow Metro
Passenger rides per year: 2.348 billion (2010)
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Seoul Subway
(Seoul Metro, SMRT and Seoul Subway Line 9 only)
Passenger rides per year: 2.173 billion (2009-2010)
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4. Shanghai Metro
Passenger rides per year: 1.884 billion (2010)
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5. Beijing Subway
Passenger rides per year: 1.869 billion (2011)
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6. Guangzhou Metro
(including FMetro)
Passenger rides per year: 1.64 billion (2011)
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7. New York City Subway
Passenger rides per year: 1.604 billion (2010)
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8. Paris Metro
Passenger rides per year: 1.506 billion (2010)
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9. Mexico City Metro
Passenger rides per year: 1.410 billion (2010)
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10. Hong Kong Mass Transit Railway
Passenger rides per year: 1.366 billion (2011)
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11. London Underground
Passenger rides per year: 1.107 billion (2010)
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12. Osaka Municipal Subway
Passenger rides per year: 837 million (FY 2010)
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13. Cairo Metro
Passenger rides per year: 805 million (2009/2010)
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14. Saint Petersburg Metro
Passenger rides per year: 777.3 million (2010)
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15. Sao Paulo Metro
Passenger rides per year: 754 million (2010)
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16. Singapore Mass Rapid Transit
Passenger rides per year: 744.8 million (2010)
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17. Madrid Metro
Passenger rides per year: 642 million (2009)
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18. Santiago Metro
Passenger rides per year: 621 million (2010)
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19. Prague Metro
Passenger rides per year: 578.5 million (2010)
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20. Taipei Metro
Passenger rides per year: 566.4 million (2011)
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21. Vienna U-Bahn
Passenger rides per year: 534.4 million (2010)
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22. Berlin U-Bahn
Passenger rides per year: 508.9 million (2009)
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23. Kiev Metro
Passenger rides per year: 504.3 million (2010)
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24. Delhi Metro
Passenger rides per year: 459.5 million (2010-2011)
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25. Caracas Metro
Passenger rides per year: 484.6 million (2009)