Where in Washington DC is the nation's most incredible treasure chest? It's a library unlike any other in the world, the U.S. Library of Congress in Washington D.C. Modern Marvels explodes the myth that this 200 year old institution is simply "where members of Congress borrow books". Viewers are taken beyond the magnificent Jefferson Building Great Hall into the secret vaults where more than 600 miles of shelves hold 130 million items, many of them priceless treasures - from George Washington's hand-written diaries to Galileo's first images of the moon to the original camera film of the movie Frankenstein. See how a staff of 4000 catalogues protects and preserves these treasures and distributes them globally via a new World Digital Library.