This still-active Cistercian Abbey was founded by Margrave Leopold III of Babenberg as a burial place for his family. Its church and cloisters, whose ancient stained-glass grisaille windows depict members of the Babenberg family, all date from the Middle Ages. The other buildings and decoration mostly date from the 17C and 19C. Many works by the Venetian Giuliani (1663-1744) are displayed here.