Fort of the Duque Hill

Category: Military Architecture > Fortress

District: Lisboa > Lisboa > Lisboa > Restelo

Location

The Alto do Duque Fort rises in the parish of Restelo, Lisbon, integrated into the southwestern area of the vast Monsanto Forest Park. Its position is remarkably elevated, at an altitude of approximately 75 meters, giving it a dominant position in the urban landscape stretching between the areas of Restelo, Algés, and Pedrouços. This strategic elevation was decisive for its original function.

Origins and Historical Role

Built between 1875 and 1890, the Alto do Duque Fort is part of the defensive complex known as the Lisbon Entrenched Field. Its construction, on land that once belonged to the Duke of Cadaval's estate, was primarily aimed at defending the Tagus River bar, acting in conjunction with the Bom Sucesso Fort, on the Monsanto fortifications line.

Throughout the 20th century, the fort witnessed and participated in crucial moments of Portuguese history. In 1936, for example, the Alto do Duque Fort went into action, responding to the artillery fire from mutinous Portuguese ships attempting to leave the Tagus, in the context of the Spanish Civil War. Later, after the Carnation Revolution, it was the headquarters of the Operational Command of the Continent (COPCON) and one of the targets of the March 11, 1975 Attempt, an event that marked the political turmoil of the time. The fort maintained military and strategic security functions, housing various entities to this day, and is currently the headquarters of the Criminal Investigation Division of the Lisbon PSP.

Architectural Characteristics

The architecture of the Alto do Duque Fort is distinctive, standing out for its irregular pentagonal plan. The construction was designed to be mostly buried, at ground level, and is surrounded by a rectangular section moat, a classic element of fortifications. It features a staggered volume and a central redoubt covered by a hemispherical dome.

Inside, the fort is organized into two main bodies, separated by the moat and joined by a wooden bridge to the south. The outer body, to the west, houses the barracks, a two-level building with rhythmically placed openings and ventilation shafts. The central redoubt, accessed by a walkway, reveals a circular interior with a notable central cistern with a groined vault, whose mushroom-like structure is a particular feature, and radially arranged compartments on two levels, with polychrome tile wainscoting and stone details.

License: https://creativecommons.org/licenses/by-sa/4.0/deed.pt