Trinity College Library, Ireland Bibliothéque Nationale de France, France The Library of El Escorial, Spain Biblioteca Geral, University of Coimbra, Handelingenkamer, Netherlands Abbey Library of St. Gallen, Switzerland Admont Abbey Library, Austria Melk Monastery Library, Austria Strahov Monastery Library, Czech Rep. Clementinum National Library, Czech Rep. Spectacular Libraries in Europe. (via Mental Floss)