Nicaragua’s 372 mounds suggest a community built them, not a ruler
On a hillside in central Nicaragua, hundreds of earth-and-stone mounds sit in a huge semi-circle, and none of them seems to belong to a king. A new study in the journal Antiquity reports that the site of Aguas Buenas holds at least 372 mounds across more than 30 hectares. After a round of fieldwork in 2025, the team found no sign of a ruler’s compound. Instead, the mounds appear to have grown and been renewed in stages, likely by the community itself.
A mound city in the Chontales highlands
Aguas Buenas lies in the Chontales department of central Nicaragua, in the Mayales River sub-basin near the Valley of Juigalpa. Archaeologists have known about the mounds for years, and excavations in 2011 to 2013 gave only limited information. Those earlier digs found few artifacts and no clear layering.
Dita Auzina of Leiden University led the new work, together with colleagues from Vrije Universiteit Brussel, KU Leuven, the Museo Comunitario de Juigalpa and the University of Oxford. Their short report appeared online on 4 November 2026 as an open-access Project Gallery article titled Revealing slow monumentality.
The scale is striking. Earlier estimates suggest that builders moved about 50,000 cubic meters of stone, which would take at least 426 person-years of labor. Ceramic comparisons place activity at the site between roughly AD 300 and 900, while two earlier radiocarbon dates fall between AD 404 and 666.
How the team read the mounds
In 2025 the researchers tested 20 mounds. Each received a 1 by 1 meter pit on its summit. They described the soil layers in the field and recorded the pottery and stone tools in each layer. They also used portable optically stimulated luminescence (pOSL), a field technique that measures how much light-sensitive energy buried grains have stored. The readings help sort one building or deposit episode from the next.
Each mound showed between 6 and 14 distinct layers. Many followed a similar order: soils rich in volcanic ash, then ceramic deposits, then pink rhyolite, then a white rhyolite cap that was probably burned. At least 10 mounds received that white cap more than once, and nine had ash layers beneath them.
No ruler’s compound, but plenty of care
The pattern suggests that no single construction project produced the mounds. The authors argue that people built, used and resurfaced them again and again. They read the repeated white capping as a sign that keeping the mounds looking a certain way mattered for a long time. They call this idea slow monumentality: a monument that grows through many small acts of upkeep, not one grand order.
The study reports no evidence for an elite authority able to direct large-scale labor, and it points to communal organization instead. The inner rectangle of the site produced more pottery, stone tools, wattle and daub and charcoal, which hints at a more sustained human presence, perhaps tied to building and maintenance work. The outer mounds saw little everyday habitation, yet four of the 15 excavated there had large ceramic vessel deposits beneath them. The authors suggest these may reflect communal consumption or deliberate offerings.
Why it matters for Central America
Many people link monumental architecture with kings, tribute and centralized states. Aguas Buenas suggests another route. Communities in southern Central America may have built lasting public landmarks through shared, repeated effort, without a ruler at the center. That gives researchers a way to study monuments in regions that lack palaces or royal tombs.
What we still do not know
The authors stress that these results are preliminary. Portable OSL gives only a relative order of events, not calendar dates. Laboratory luminescence dates are still pending, so no one yet knows how long building lasted or whether the mounds rose over decades or centuries. Radiocarbon dating has been limited by a lack of organic material, and the ceramic dating spans a wide window. The purpose of the site also remains uncertain, and some ideas, such as volcanic ash playing a role in construction, appear only as possibilities. Further micromorphology, pottery, stone tool and ash analyses are planned.
For now, Aguas Buenas stands as a reminder that big does not always mean royal. A community may have kept shaping its landscape for generations, one fresh white cap at a time.