Nestled along the south bank of the Danube, this historical Austrian city bursts with charm. A favorite stop on European river cruises, the city's most famous attraction is Melk Abbey, which dates back to the 11th century. The original Benedictine structure was lost to fires and foreign invasion, then rebuilt during the 18th century in lavish Baroque style, including a library and inner church covered in magnificent frescoes and gilded fixtures.