Library of Congress, District of Columbia

Located in Washington, D.C, the Library of Congress is a research library focusing on the study of the United States Congress. It is also the oldest federal cultural institution in the country as well as one of the two largest libraries in the world, together with The British Library. Although it contains more than 151 million items, ordinary visitors can't check out books. However, the spectacular architecture and glorious interior decoration make the library definitely worth a visit.