Maybe the British Library is the World's Largest Physical Library

The British Library with about 150,000,000 physical items on 625km of shelves might have been the world's largest physical library in 2005, though the U.S. Library of Congress also made this claim. The British Library added about 3,000,000 physical items per year, which occupied about 12km of new shelving. At the end of 2005 the Library of Congress held about 130,000,000 physical items and had more than 8,000,000 digital items online.