The entry area consists of the Rondell, the Great Tower and the Elizabeth Gate. The southeast corner is formed by the Broken Tower gutted by the French in 1693. The Gothic hall of the Well Wing contains Roman columns originally from one of Charlemagne's palaces. Worth seeing: the Library, Friedrich Wing, Otto-Heinrich Wing, gardens, Pharmaceutical Museum and Gross Fass, a gigantic vat with a capacity of 221 726 litres.