The growing interest in the heritage that contemporary society carries with it, and which is reflected in the extent of the debates and issues relating to its preservation and enhancement, runs up, most of the time, to the authentic memory / memory dichotomy. Dynamic. That being said, the reuse of built heritage in the process of renewing the image of our cities (use-value) becomes dependent on a global conception included in a sustainable urban development approach.

The monumental heritage, subdivided, generally, into five categories namely; religious, hospitable and funeral, civil (public or private), agricultural and industrial and finally military, raises enormous problems as for its reuse. These are more pronounced towards the military-defensive architecture that is the subject of this contribution.

In Algeria, defensive architecture occupies an important part in its heritage site. The typological diversity –the result of a long stratification from the early antiquity to the middle of the last century– as well as the dominant position occupied by this defensive heritage abandoned in the current urban landscape imposes a more urgent care.

Therefore, we want, through this communication, to lay the first steps of a patrimonial approach to highlight this or these unknown military architectures and preserve our defensive heritage for which the collective memory is not attested and still painful.

The reuse of the defensive heritage in Algeria must first and foremost go through its identification, inventory its various typologies, evaluate its current physical impact and finally explore the different urban alternatives that will result from its reintegration into the urban experience and for sustainable cities and citizens.