bastiones

Bastiones, known in English as bastions, are projecting parts of a fortification that extend outward from the main curtain to improve the defenders’ field of fire along the walls. The outward angle allows enfilading fire on attackers approaching the fort and reduces the effectiveness of siege artillery against the curtain.

A typical bastion has two faces that meet at an exterior angle, forming two flanks that project beyond the rest of the fortification. Parapets, embrasures for guns, and internal constructions are arranged to cover fire along adjacent sections of wall. Surrounding elements such as ravelins, hornworks, or demi-lunes are outworks designed to disrupt assaults before they reach the bastion. The glacis, a sloped earthen slope, and moats provide additional defense.

Development and use: Bastions emerged in late medieval and early modern fortifications, becoming standard in the star fort or trace italienne designs of the 16th to 18th centuries. They were optimized for artillery and refined by military engineers such as Vauban. Bastions were widely adopted across Europe and in colonial settings, influencing fort-building around the world.

Today many bastions survive as historical monuments. They are studied within military architecture and preservation efforts, and some remain integrated into urban landscapes or protected as UNESCO sites.