The New York Public Library just spent $23 million to create a gigantic storage space beneath Bryant Park to stash millions of books. Our Michael Scotto takes look.

This book is winding its way through the New York Public Library on a high-tech $2.6 million track system that cuts through 11 levels of the main library on 5th Avenue.

"This allows us to deliver multiple items versus having to have someone carry, physically carry it up the building to its delivery point," Gerry Oliva, who works for the library's department of facilities management.

The tracks replace an old conveyor belt system that had grown obsolete. They will soon be shuttling books to the famous reading room, which will re-open next month after a multimillion-dollar renovation.

"This is the circulation system of the largest collection at the New York Public Library," said Matt Knutzen.

When a request comes in, workers spring into action. They look for the book, bring it to one of these containers, push a few buttons. And it's off.

Five minutes after it's placed on the track, the book arrives upstairs.

Many of the books are stored right here in these brand new stacks some 27 feet below Bryant Park. 

Completed in the spring, the facility cost $23 million to build-out.

It's the size of a football field and sits right below stacks that were constructed in the 1990s.

Combined, the two rooms can hold some four million books, which are arranged by size to maximize space.

The relative humidity is kept at 40%, the temperature at 65 degrees.

"There are also a lot of backups and things like that where we have sensors, so that if there is a level of moisture the system is able to detect it and alarms set off," said architect Anthony Harris.

Workers have been moving reference books to the new stacks since the spring. During the renovations, they had been stored in Westchester County — to the annoyance of patrons. The books, back in the old library, now have a more modern home.