New York Public Library Main Branch

The story

The New York Public Library's Main Branch stands on the bones of a reservoir. The Croton Reservoir once occupied this Fifth Avenue site before Carrère and Hastings raised a Beaux-Arts marble facade in its place, opening the doors on May 23, 1911. Formed from the merger of two libraries in the late 1890s, the institution grew into a research colossus holding an estimated 2.5 million volumes by 2015. A National Historic Landmark since the 1960s, it remains one of four research libraries in the system, its nine divisions spread across four public floors.