Many castles and fortifications dating from the Crusader period have been excavated and restored within the state of Israel. Some almost resemble historical theme parks, but others have been treated more sympathetically. The Old City of Acre was one of the few Palestinian towns to retain is Arab population following the mass expulsions of 1948. This, when added to the skilful, sensitive and restrained manner in which Israeli archaeologists are still uncovering the ruins of the medieval city, makes Acre a top priority for those seeking Crusader fortifications in the Holy Land. Pilgrims' Castle at Atlit, south of Haifa, is still out of bounds because the location is currently used as a training base for Israeli Naval Commandos. However, the dramatic fortress is clearly visible from the coast. Southward again, the excavated site of Caesarea contains remarkable remains from many periods, of which the 13th-century Crusader fortifications are the best preserved. The equally remarkable but smaller and less known site of Arsuf lies on the coast just north of Herzliya. It was another closed military zone until a series of explosions and chemical leaks convinced the Israeli Defence Forces to move their weapons development facility from the site. Nevertheless, until the existing toxic pollution is removed, archaeological excavations and public access to the remains of medieval Arsuf will remain restricted.