Zwickau is rich in unique monuments and buildings and squares worth seeing. The Ratsschulbibliothek ('council school library') is the oldest public and scientific library in Saxony, the Priesterhäuser ('priests' houses') are among the oldest preserved residential ensembles in Central Europe and the Johannisbad swimming bath is an Art Nouveau gem. In addition to unique museums, Zwickau is home to monuments of supra-regional importance, such as the medieval Kornhaus (granary), the Katharinenkirche (St. Catherine's Church), which has been awarded the European Heritage Seal, and the Dom St. Marien (St. Mary's Cathedral).