At the turn of the 20th century, slow and inefficient public transportation stifled the growth of what was then the world's second-largest city. So New York went underground.

Now the New York City subway system (search) is celebrating its 100th anniversary.

"The subway itself helped turn the city into the great metropolis that it is," said transit historian Joseph M. Calisi.

It took 30,000 worker, primarily African-Americans and Irish and Italian immigrants, to move the millions of tons of dirt, sand and rock dug out to create subway tunnels.

On Oct. 27, 1904, the city's first regularly schedules subway train rolled out of City Hall Station.

On that first day, 150,000 people paid 5 cents each to ride the Inter-Borough Rapid Transit (search ) train. The inaugural atmosphere was described as being like a New Year's Eve party. "From City Hall to Harlem in 15 minutes" was the catchphrase back then.

But 40 years later, the opulent City Hall station, with its arched ceilings and beautiful chandeliers, closed. Its curved platforms were too short to accommodate the newer, longer trains.

Soon afterward, also gone were cars with wicker seats and ceiling fans to keep passengers cool.

Nowadays, tokens have been replaced by Metrocards. Passengers who used to travel in graffiti-covered cars now enjoy sleek, stainless-steel ones.

There are now 4.5 million daily riders, 26 lines, 842 miles of track and nearly 500 stations. Though not the largest subway in the world, it's billed as one of the most efficient and has always had a certain mystique about it.

"There's a nickname for the New York subway. It's called 'The Daily Miracle,'" said Calisi. "I mean, when you look at it this way, when there's this many people running this many trains on this many lines, I mean you just sit back and say, 'Wow.'"

Click on the video box near the top of this story to watch a report by FOX News' Todd Connor.