The structure consists of three concentric walls up to five meters high and 25 towers. Inside, the tomb of a possible Roman legionary has been discovered.

© Tera S.L.Aerial view of the Copper Age fortification located in Almendralejo.
Some 4,900 years ago, during the
Copper Age, a group of humans constructed a formidable fortress on a hill in what is now the Spanish city of Almendralejo in Badajoz province. This stronghold was protected by three concentric walls, 25 bastions or semicircular towers, and three deep ditches measuring up to four meters wide and two meters deep. Spanning 13,000 square meters, the complex featured robust stone and adobe walls, with a single entrance just 70 centimeters wide — designed to make it virtually impregnable.
Yet, despite its formidable defenses, the fortress was ultimately destroyed, burned, and razed by enemies, then abandoned 400 years after its construction.
The archaeological research team at Tera S.L. uncovered this site in 2021 and continues to excavate it. Its characteristics closely resemble those of Los Millares in Almería province, the reference model for
Chalcolithic settlements in the southeast of the Iberian Peninsula.
Who attacked and destroyed this fortification, how they did it, and what exactly it was built to protect remain unanswered questions. "But we are getting closer," says César M. Pérez, director of the excavations.
In addition to the structure itself, archaeologists have uncovered numerous artifacts within the site, including arrowheads, idols, axes, grinding stones, plates, bowls, and loom components. These findings, along with other materials, provide valuable insight into the activities that once took place inside the fortification.
According to the archaeological research team, the pentagonal fortress — the first to be built atop a hill 314 meters above sea level — offered a commanding view of the surrounding landscape. Its original structure featured an adobe wall between 1.3 and 1.5 meters thick, five bastions, and a single entrance described as being "shaped like crab claws."
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