(CBS News) NEW YORK - In a city known for iconic buildings, Grand Central Terminal is a jewel in New York's crown.
The ornate landmark turns 100 years old this week. A couple of generations ago, it almost fell to the wrecking ball, but it survived in better shape than ever to celebrate its centennial.
For one hundred years, Grand Central Terminal has been the heart and hub of New York City. It's one of the largest, and busiest, spaces in New York.
"It is very big, and it was when it opened the largest interior space in New York, and it is now -- by number of tracks and platforms -- the largest railroad terminal in the world," said Sam Roberts, an Urban Affairs columnist for the New York Times and author of the book "Grand Central."
Roberts says the terminal did more than just transform the city - it became synonymous with an America on the move.
"'This place is as busy as Grand Central Station'; what other building do we use that same simile for? When you talk about the fact that there was a radio station here, every Saturday people longed to listen to [it] because they had these romantic tales of New York City," Roberts said. "That films were made here - 'North by Northwest.'"
Upstairs, where the tennis court is now, were the original CBS TV studios, home to Edward R. Murrow and "What's my Line?"
Forty years ago, Harry Kelly, then a kid from the Bronx who'd never been to Grand Central, came to work here.
"When I first walked into the place I was like, my God," Kelly said.
But by the time Kelly started, Grand Central had fallen on hard times.
"The funny thing in the 70s ... we couldn't even see each other [because of the smog]. I could maybe see the wall, but everything was diesel. You'd be choking. This whole area would be black with diesel smoke," Kelly said.
Roberts said in the 70s and 80s, the place was "a dump."
"There's no question about it," he said. "Homeless were sleeping in what used to be the waiting room; they were sleeping in the tunnels below the station. There was grime, there was soot."
The owners wanted to tear it down, just like the original Penn Station, another New York landmark. But Grand Central had a powerful champion: Jacqueline Kennedy Onassis.
"Jackie-O was instrumental to saving Grand Central," Roberts said. "Penn Station, you could argue, didn't die in vain. It spawned a landmark preservation movement and Grand Central was one of the chief beneficiaries of it."
Finally, after years of neglect, the terminal was restored to its original grandeur: The iconic clock, its faces made of opal, the display board showing all departures one minute early to give you a little extra time, the Tiffany glass clock outside and the image of the constellations on the vast ceiling.
"It's funny, because when I did the book, it's really a biography of the building: People who come here, work here, who earn their livings here, who pass through here. And they're what this palace is all about. And when you stand on the balcony over the concourse, it appears like an urban ballet," Roberts said.
After it was completed in 1913, the New York Times predicted the terminal would eventually handle 100 million people a year. A hundred years later, according to Roberts, that's about to happen. Eighty-two million people passed through last year and with expansion projects under way, the total is likely to reach 100 million in a couple of years.