The relationships between the Ottoman Empire and Venice, the Adriatic and Central Europe strongly influenced the social and urban order of a city model that paid tribute to Asia and the West but is also far from the principles of the eastern Mediterranean city and from those of the walled European city (whether Greek or Arab). The differences are formal and structural, even though the district (mahalle in the case of the Ottoman city; khitat in North Africa) constitutes the foundational unit of the urban fabric, both in the open Ottoman model and in the closed, North African for instance, one (consider the Tunisian cities of Al-Kairawan and Nabeul). First and foremost, unlike the Mediterranean medinas and European walled cities, the Ottoman city is an open city, not enclosed by walls (unless they date from an earlier period), therefore, in a relationship of continuity with the surrounding countryside, the expression of an urban society that appropriates the rural world: this is why the architecture of the city is, fundamentally, a landscape architecture. The Ottoman settlements extend into the countryside, going beyond the traditional contrast between architecture and nature specific to European and Arab-Islamic walled cities. The former sites are usually characterised by special topographical and landscape conditions, which document how the origin of Ottoman settlements is to be sought in the link with the architecture of the soil rather than with a geometric plane: it is the site that determines the choice of settlement and type.