At the beginning of the 1990’s the structural condition of the Hall of Pillars in the Knights Hospitaller compound became unstable. This became apparent when cracks started to appear in the vaults in the hall and soil and mortar fell from the vault’s core into the hall below.

In the wake of engineering measures that were adopted to save the hall, the Old Acre Development Company decided to go forward with the restoration and development of the underground complex for tourism purposes. This decision resulted in an extensive archaeological excavation, which was conducted from 1992 to 1999 by the Israel Antiquities Authority and financed by the Ministry of Tourism.