forts

Forts are fortified military structures built to defend territory, host garrisons, and control important routes. They may stand alone or be part of a larger fortress system and are designed to withstand siege rather than function as ordinary residences. The term fort is often used for permanent works; fortress refers to a complex of defenses surrounding a site, while castles are medieval residences that also provide defense but emphasize residence as well as fortification.

The idea of fortification stretches from ancient walled enclosures and towers to medieval stone castles, then to early modern star and bastioned fortifications shaped by gunpowder artillery. The 17th–18th centuries saw engineers like Vauban producing interconnected systems that could defend a region and enable rapid defense. In the 19th and 20th centuries coastal batteries, border forts, and field fortifications expanded the range of defensive works. In contemporary times, many forts are no longer frontline defenses and have become museums, tourist sites, or preserved heritage; others continue in limited military roles or as secure storage.

Design features commonly found in forts include thick walls or ramparts, bastions or flank defenses, moats or ditches, glacis, drawbridges, embrasures and casemates for artillery, and magazines or cisterns for supplies. Interior layouts often accommodate barracks, workshops, storage, and tunnels or shelters.

Types cover hill forts, earthworks, stone forts, coastal forts, border forts, fortress-cities, and citadels as inner strongholds. Fortifications remain important for understanding military architecture, archaeology, and urban history.