Bejaia, is a coastal city of Central-East Algerian which has seen succeeding on its lands several civilizations: Byzantine, Roman, Hammadite, Spanish and Ottoman

It reached its peak from the beginning of the eleventh century, when the Hammadite ruler, An-Nasir made it the capital. The city maintained this important status until the sixteenth century, when it was considered the jewel of the Maghreb.

At that time, the city was fortified with a large surrounding wall, which spanned more than 5000 m. This city wall was flanked with bastions and towers, and rose in tiers from the sea-side to Mount Gouraya. Its layout was perfectly designed and blended with the city’s topography

It consisted of three walls: one to the east and another to the west, which were connected by a third wall, which ran along the seaside.

Today, two gates are preserved from the city of Bejaia’s rich defensive heritage: Bab El Bahr, which opens onto the sea, and Bab El Fouka, which opens onto the plains, as well as some parts of the walls, dotted around different parts of the city. This heritage is threatened and its preservation, restoration and enhancement require a comprehensive knowledge of the architectural and constructive styles, which characterize it, and of the materials used in its construction.

This contribution aims to identify the architectural and constructive features of this defense system, developed by the Hammadites, as well as a characterization of the construction materials used, such mortar, through physical, chemical and petrographic analyses.