The Library of Congress in Washington DC is essentially both the national library of the U.S. and the country’s oldest federal cultural institution. Though it consists of only three buildings, it is the largest library in the world for shelf space and number of volumes. While open to the public for on-site research and as a tourist attraction, as the research institution of Congress, only members of Congress, Supreme Court justices, and other specified government officials can check out books. The library is formally known as the “library of last resort” in the U.S., charged with making certain items available to other national libraries if all other means have been exhausted. The library’s holdings are vast, including more than 32 million books, more than 61 million manuscripts, a rough draft of the Declaration of Independence, one of only four perfect vellum copies of the Gutenberg Bible in the world, over one million newspapers from the last three centuries, over five million maps, six million pieces of sheet music, and more than 14 millions photos and prints.