A natural centre of the walled city's defences, protected by steep cliff faces, this ancient castle with its two square towers can be seen from afar. The restoration carried out from 1982 to 1992 has transformed the edifice into a city park. The buildings in the southern courtyard house a museum. The archaeological section charts the history of humankind in this area. The most interesting section is the very rare collection of 144 tablets painted in the 15C.