Minas y Galerías. El sistema defensivo subterráneo de la plaza de Orán

The city of Oran, located in northwestern Algeria, is one of the most famous presidio of the Spanish crown between the XVI and XVIII centuries. The fortified city has one of the most developed defensive systems in North Africa, with more than twenty fortified works built by important engineers of that era. This article offers the result of the documentary investigation, from diverse historical archives sources, of those reports and cartography included between the XVI and XVIII centuries. The investigation deduces the organization of the defensive system of Oran and focuses on the analysis of its prodigious network of underground mines and galleries.