​The restoration of St. Patrick's Cathedral

Pope Francis saw the truth of the saying "What's Old Is New" when he visited St. Patrick's Cathedral in New York this past week. And now, with Mo Rocca, we can, too:

Every Sunday morning in New York, the bells of St. Patrick's echo through the city, beckoning Catholics and non-Catholics to the Cathedral's massive bronze doors.

Welcome to St. Patrick's Cathedral, "America's parish church."

"We've got over six million people a year that come through here," said New York's Cardinal Timothy Dolan. "They want to see St. Patrick's."

And there is a lot to see. A neo-Gothic landmark, St. Patrick's is bathed in natural light through a prism of stained glass -- an expression of uplift and hope deeply-rooted, says New York's Cardinal Timothy Dolan, in the American experience. "Almost all of the great ethnic parades -- Columbus Day, the Steuben Day Parade, the Puerto Rican Day Parade -- begin with mass here at St. Patrick's, St. Patrick's Day, of course, being the biggest!"

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Cardinal Timothy Dolan with correspondent Mo Rocca.
CBS News

It was the flood of Irish immigrants in the middle of the 19th century that gave birth to St. Patrick's Cathedral. Fleeing famine and persecution, Irish Catholics were met with hostility here in America. But they found a champion in Archbishop John Hughes.

"His nickname was 'Dagger John,' because he would stand up and defend the rights of his people who were very poor and were very forgotten," recounted Dolan. "And he said, 'We want to make a statement: I want to build a cathedral of suitable magnificence to make the statement Catholics have arrived; they are at home.'"

To build St. Patrick's, the archbishop turned to James Renwick, Jr., designer of the Smithsonian Castle in Washington, D.C., and considered the premier American architect of the time.

It took more than 25 years of mostly immigrant labor to realize Renwick's vision, and when its twin spires were completed in 1888, St. Patrick's stood as the tallest building in New York City.

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Cleaning the spires of St. Patrick's Cathedral.
© John Baer

"Isn't that phenomenal?" said Dolan. "And we're still proud of its grandeur and its size."

But after years of neglect, the Cathedral was showing its age. "This Cathedral, simply put, is cracking," the Cardinal said before his congregants. "The bricks are crumbling and falling."

Which is why in 2012 Cardinal Dolan announced a restoration of St. Patrick's, at an eye-popping price tag ($175 million) at the same time that parishes and schools are being closed. "Here's the only answer I can give: We had to do it. It was survival," said Dolan.

Architect Rolando Kraeher, of the firm Murphy, Burnham & Buttrick, was charged with overseeing the daunting task.

Kraeher noted that the Cathedral is constructed from Tuckahoe marble: "Tuckahoe marble is a beautiful, wonderful stone, but it's very soft. And we found some areas where the stone, to the touch, it would pulverize in your hand."