The Shali citadel (XII century) and building culture in the Siwa oasis. The recount and results of an investigation

The research concerns the peculiar and unknown building technique utilized in the construction of Shali, ancient fortress built in the XII century in Siwa, an oasis of the western Egyptian desert. The architecture is characterized by the use of salt blocks, taken from the nearby salty lakes. The report summarizes an investigation aimed at understanding construction techniques and structural behavior of this original artifact; finally a pilot intervention around the North Gate of the fortress is shown together with the guide-lines proposed for the conservation.