The 900-year-old Hohensalzburg Fortress is the biggest and most fully-preserved fortress in Europe, built by Archbishop Gebhard in 1077, used to serve and protect the clergy and the population.Salzburg Cathedral is a 17th-century Baroque cathedral and the most important early baroque building north of the Alps. After having burned down by lightning in 842, it was also bombed in WWII, repeatedly destroyed, rebuilt, enlarged, modified, and extended.