Since the doors of the first subway train opened in 1904, New Yorkers and tourists alike have been fascinated, amused, amazed, repelled and bewildered by the world-within-a-world that lies beneath the city.

Now, as the subway celebrates its centennial anniversary, the creator of The New York Times's award-winning "Tunnel Vision" column leads us on an extended tour of this storied subterranean land, revealing:

* Its inhabitants: the Tango Man, the traveling magician, Mayor Bloomberg
* Its wildlife: the subway-riding pigeons, the Fulton Street cat, the blind mules
* Its customs, taboos and secret histories: door blocking, leg spreading, pole hugging, even, yes, token sucking
* Its government: the sheriff of Grand Central, the Ethel Merman of the shuttle, the motorman who drove the last No. 1 train beneath the World Trade Center on September 11, 2001
* Tips for the first-time traveler: how to get a seat, how to get a date, the fine art of "pre-walking"