The Law Library of Congress is the largest law library in the world, and much of its vast collection is housed in the Madison Building’s sub-basement stacks. Whenever a patron requests an item that does not have “RR” at the end of the call number, our expert staff combs through our vast collection of over 2.5 million volumes to locate the item and fulfill the request. The stacks are equivalent to one and a half football fields in length, and hopefully this stereoview, which depicts just one quadrant, will give you some sense of how truly enormous this space is.