A Fortress on a Hill
The Quilmes settlement is a sprawling pre-Hispanic city built into the slopes of the Cerro Alto El Rey mountain. Covering 30 hectares, the city shows a high-density urban plan with a clear organizational structure. The residential sector is located in the lower areas, characterized by stone structures with rectangular and circular layouts. These houses typically had a central open patio that functioned as a living, working, and storage space. The builders used a dry-stone construction technique with locally sourced schist, fitting rocks together without mortar. Some buildings feature double walls for insulation against the extreme temperatures of the semi-arid climate.
Higher up the slope, the city's defensive nature becomes apparent. The structures form a classic pucará, or hillside fortress, a common feature in the Andean region. This strategic location provided clear views of the surrounding Calchaquí Valley. The upper reaches of the settlement contain the remains of a citadel, which was the last line of defense for the community's leaders and warriors. The entire city shows an understanding of defensive architecture, which allowed the Quilmes people to resist Inca expansion in the 15th century and Spanish forces for 130 years.
Engineering for a Dry Climate
Survival in the arid Calchaquí Valley depended on precise management of water and land. The Quilmes people engineered an extensive system to support their population of approximately 5,000. Around 50 hectares of agricultural terraces, known as andenes de cultivo, are carved into the hillside. These terraces, reinforced with rock walls to prevent erosion, were used to cultivate crops like maize and quinoa.
To irrigate these fields, the Quilmes constructed dams and canals to capture and channel rainwater. A major reservoir near the top of the settlement had the capacity to hold over 7 million liters of water. Its retaining wall was a significant engineering feat, built with stone slabs and measuring 17 meters long. The wall was designed to withstand immense pressure, tapering from one meter thick at the top to three meters thick at its base. This complex water system was important for the community's self-sufficiency and its ability to withstand long sieges. The eventual defeat of the Quilmes in 1667 came after Spanish forces managed to disrupt their access to this important water supply.