Founded in 1899, this is 1 of only 16 nonprofit membership libraries in the United States. Year-round, it hosts exceptional art exhibits, intimate concerts (from jazz and classical to more experimental new music), lectures, special events, and classes that are open to the general public. An incredible collection of books, music, and more makes for fascinating browsing, but only members can check something out. The Athenaeum has been located at this site from the very beginning and over the years has expanded into adjacent buildings, including the beautiful Spanish Renaissance-style rotunda, designed by renowned architect William Templeton Johnson and dating to 1921. Free tours are conducted every third Saturday at 11am.