It is a terrible prison underground, endless corridors and engineering masterpiece reflects the strength and prosperity of Morocco during the reign of Moulay Ismail, whom you feel the presence of his mark on each wall in the historic city of Meknes.It is a prison built by Moulay Ismail to hurl his opponents.A prison built entirely underground. It was built such as the corridors of a maze. Each hall leads to several corridors and each corridor leads to another room so that it becomes very difficult to come back where you came from. It is said that no one has entered this prison came out alive.