A century-old Italianate structure of bronze doors and grand marble staircases, Boston Public Library — the first large public library in the nation — holds 6 million books and sees 2 million visitors annually. Priceless holdings include first edition folios by Shakespeare, original music scores by Mozart and Prokofiev, and the personal library of former President John Adams. The cool interior features murals by John Singer Sargent and a relaxing courtyard.