From a colonial battery to a detention centre

Construction of the Peñas Altas battery began in 1818 and was completed in 1821 as part of the Spanish colonial defensive system protecting the eastern flank of the Bay of Matanzas. The installation comprised a semicircular shoreline barbette wall and an internal building with officers’ quarters, barracks, kitchen and powder magazine, while latrines were positioned outside the eastern perimeter wall. Between 1875 and 1886, a major expansion extended the battery to the south-east and added new artillery platforms (Figure 1).

Figure 1. Historical cartography showing the development of the Peñas Altas battery (source: Madrid Military Historical Archives).

During the first US intervention in the early twentieth century, Peñas Altas was converted into a powder magazine and ammunition depot. Following the Sergeants’ Revolt of 1933, widespread reorganisation of military facilities took place, including at Peñas Altas, where the Marine Infantry Barracks subsequently operated. By 1946, the site had been repurposed as a Public Works warehouse while the Rural Guard’s motorised unit established a presence there.

A major transformation occurred in January 1958, when Escuadrón 41 of the Rural Guard relocated from the Versalles neighbourhood to Peñas Altas. It was during this period that the site served as a detention and torture centre, where numerous revolutionaries were imprisoned—some beaten to death, their bodies discarded on the outskirts of the city.

After the Cuban Revolution in 1959, the installation remained in military use, serving as a training ground for Militias, including units deployed during the Bay of Pigs invasion in April 1961. Shortly thereafter it was demolished, and by 1962 the site lay in ruins. In the late 1970s, urban development replaced this void with a tower-block of apartments, burying much of the colonial battery beneath construction debris and converting the area into a park and playground, sanitising the landscape and erasing its traumatic past. A new road bisected the former compound, creating two zones: one marked by a discreet plaque installed in the 1980s, the other left unmarked and forgotten.

Archaeological fieldwork

Archaeological fieldwork at Escuadrón 41 employed systematic mapping, excavation of select areas, 3D photogrammetry, ground-penetrating radar, underwater survey, architectural documentation, extensive archival research and interviews with survivors and community members. Together, these methods reveal a complex material and social palimpsest shaped by cycles of violence, abandonment, transformation and everyday reuse.

Excavations documented the longue durée of the site, from its colonial origins to the twentieth century, exposing architectural modifications, buried ashlar walls and material traces of daily life discarded into the latrine. Underwater surveys recovered ogival projectiles associated with the opening battle of the Spanish-Cuban-American War in 1898, contributing new evidence to the military history of the Peñas Altas battery (Figure 2).

Figure 2. Underwater 3D photogrammetry of the area; white squares mark where ogival projectiles from the 1898 Spanish-Cuban-American War were documented (3D model by E. Grau).

Excavation units uncovered portions of the former barracks, holding cells and defensive structures. Surviving architectural features—such as reinforced walls, barred openings and foundation segments of confined spaces—corroborate historical accounts of detention practices. In several units, displaced ashlar blocks, shattered plaster and irregular floor surfaces indicate episodes of deliberate demolition or post-abandonment scavenging (Figure 3).

Figure 3. Archaeological excavations showing preserved structural walls (photographs by author).

More importantly, the archaeological record demonstrates the persistence of the ruins despite efforts to erase them—physically and from public memory. Excavations served as mnemonic devices, creating a platform for surfacing untold stories, including recurring narratives about bodies allegedly thrown into an underground facility, well or cave—stories tied to individuals who disappeared and were never recovered. These memories were associated with one underground structure—a colonial cistern—known to exist somewhere at the site.

Finding the cistern became a principal objective of the project. Its location proved elusive. Buried beneath 1m of fill, sealed with two concrete lids and covered by a rebar-reinforced slab, the structure had been obscured during construction of the apartment tower. Testimonies from construction workers indicated that a temporary sewer had been connected to an existing underground feature. The discovery of ceramic sewer pipes linked to the former construction camp allowed the insertion of a stereoscopic camera, revealing a large dark chamber located roughly 1m eastward, beneath the modern garage buildings. Lateral excavations uncovered the cistern’s entrance, and interior access and excavation rejected the presence of human remains; instead, the cistern contained demolition debris from the early 1960s, along with military and personal artefacts (Figure 4).

Figure 4. Excavation unit, lateral excavation and cistern interior (photographs by author).

A burned garbage pit located along the eastern exterior of the colonial building contained military and domestic materials, including a locally manufactured explosive device—likely a firecracker or propellant—that had failed to detonate. Constructed from the base of a REM–UMC .32-calibre cartridge and a metal cylinder inscribed ‘OSCAR S. MECHOSO / MATANZAS’, the device was hand-sealed at one end (Figure 5). While an explosive device would rarely bear a full name, this one may have been improvised using components purchased from the Mechoso Store, a well-known local business dealing in electrical and radio supplies. The Mechoso name also resonates with political resistance: Juan Rivero Mechoso, a relative of the store’s owner, served as president of the Federación Estudiantil del Instituto de Matanzas and participated in the anti-Batista resistance. A top-secret report by Brigadier General Eulogio Amado Cantillo Porras linked both Oscar and Juan Rivero Mechoso to revolutionary activities (Ferrera Reference Ferrera1990), adding further historical depth to the artefact.

Figure 5. Locally made explosive device from Excavation Unit 2, likely a firecracker or propellant (photographs by author).

Fieldwork confirms that the site’s neglect and partial erasure were not incidental but closely tied to state-managed politics of memory. Stratigraphic data and recovered artefacts reveal episodes of disturbance, reuse and post-occupation modification—evidence of the site’s extended material life beyond its period of repression.

Local memory proved essential to interpreting these afterlives. Testimonies reveal layers of recollection, rumour, silence and reinterpretation that coexist uneasily with the physical remains. Some residents remember abuses committed under Batista; others recall the site mainly as an abandoned space repurposed for leisure. These shifting narratives underscore the complex interplay between materiality, memory and forgetting.

Excavating Escuadrón 41 exposes not only the scars of authoritarian violence but also the resilience of meaning, the endurance of memory and the potential for ethical and political engagement. Archaeology in such settings becomes more than a technical endeavour: it is an act of witnessing, response and care. By reading ruins through a hermeneutics of the trace, recognising the politics of forgetting that shaped their fate and embracing an ethical responsibility toward the ‘other’, archaeologists can contribute to broader struggles for justice, recognition and historical understanding.