 They were built at an altitude of 300 m along a rock wall just 1300 feet (~400 m) long by 165 feet (~50 m) wide.Cabaret, Surdespine and la Tour Régine stand in line, while Quertinheux is built on a separate pinnacle close by.The site has been classified "monument historique" (historic monument) by the French Ministry of Culture since 1905 and archaeological digs are still in progress.