Thomas Jefferson Building

The Main Reading Room of the Library of Congress, in the Thomas Jefferson Building in Washington, D.C., photographed in 2009. The Jefferson opened in 1897 as the library's first building of its own, and this room under a dome rising some 160 feet is its heart. Desks ring the central reference desk in circles, so every reader faces the middle of the room. Visitors with a free timed-entry ticket can look down on it from the overlook off the Great Hall, join a tour of the floor on Tuesday through Friday mornings, or walk in on Thursday evenings.