Now I Know: “The main branch of the New York Public Library, officially the Stephen A. Schwarzman Building, is located in midtown Manhattan — and it’s enormous. The building runs from 40th Street to 42nd across 5th Avenue, stretching about a third of the way toward Sixth. It contains an estimated 2.5 million volumes of books in its stacks with millions more in storage just a few feet away. Those stored books are in Bryant Park, a nearly ten-acre public space behind the library which, as seen above right, hosts an ice skating rink during the winter months. (The library is the building on the left, behind the illuminated greenhouse.) Beneath the park are the Milstein Research Stacks, which hold approximately four million more volumes of books across a combined length of roughly 80 miles of bookshelves. The Research Stacks, originally built in the 1980s, are virtually unknown to the thousands and thousands of people who visit Bryant Park each year; as the New York Times reported, the stacks are “17 feet below ground, in a concrete bunker worthy of the White House.” You don’t find them by accident…”