The mysterious Sillustani tombs: The last remains of an ancient culture wiped out by the Inca

Sillustani occupies a narrow peninsula that juts into Lake Umayo, which sits more than 3,800 metres above sea level in the high plain of Puno (the altiplano), and the site, located roughly 35 kilometres from the regional capital, is remote even today, accessible only by narrow roads that twist through barren grasslands and rocky hills.

Steep cliffs guard three sides of the plateau, and the fourth side faces the open lake, which reflects the sharp blue of the Andean sky. 

Few permanent settlements existed nearby because altitude, wind exposure, and arid soil limited both agriculture and habitation, yet the location offered strategic advantages to the Colla because the high vantage point provided clear views across surrounding valleys and allowed them to watch movement between rival communities.

The selection of this place for elite burials may have expressed a belief that closeness to sky, water, and earth gave spiritual or ancestral authority. 

From the edges of the plateau, the view of Lake Umayo suggested an intentional harmony between the natural environment and the human structures that rose from it, and the peninsula’s difficult terrain, together with its limited accessibility and thin atmosphere, helped protect the site from major modern damage.

For archaeologists, this preservation offered rare opportunities to study a burial centre that had shown the final stage of an independent culture before it fell to the empire. 

The Colla people held political and military control over a wide section of the northern Lake Titicaca basin during the Late Intermediate Period, which spanned from around 1000 to 1400 CE.

They organised into regional chiefdoms, spoke Aymara, and lived in fortified hilltop settlements known as pukaras, which allowed them to defend themselves against both rival Aymara groups and external threats.

Alliances and rivalries changed often, and the Colla clashed with neighbouring groups such as the Lupaca and Canas. 

Family ties formed the basis of Colla social organisation, and the ayllu were the primary unit of both identity and labour.

Each ayllu controlled specific territories, often divided across different ecological zones, and this arrangement enabled communities to cultivate multiple crops and to manage herds of llamas and alpacas.

They used terraced fields and irrigation canals, which helped them grow enough food at high altitude. 

Ritual centres and ceremonies were central to Colla identity, and the elite often used architecture to show power.

During the fifteenth century, the Inca Empire began a campaign of expansion into the southern Andes, and the Colla became one of its major targets.

Pachacuti had begun military campaigns in the region, and his son, Topa Inca Yupanqui, continued these campaigns during the 1470s and 1480s, gradually bringing the area under imperial control.

Spanish chroniclers, such as Pedro Cieza de León, recorded that the Colla resisted Inca conquest with notable strength, though they eventually came under imperial rule. 

Once conquered, the Colla elite were brought into the Inca system of government or they were displaced.

Their language and customs gradually declined, yet the tombs at Sillustani survived as evidence of their former presence and religious traditions.

Despite the lack of written records from the Colla themselves, archaeologists reconstructed parts of their society using architectural features, burial customs, and artefacts recovered from the site.

In addition, scholars noted parallels between Colla beliefs about the universe and the three-part Andean worldview, in which hanan pacha was the upper world, kay pacha described everyday life, and uku pacha denoted the underworld. 

The tombs of Sillustani, known as chullpas, showed an architectural tradition developed by the Colla for elite burials, and their round, tower-like shape set them apart from other Andean burial structures.

Built from closely fitted volcanic stones, some towers rose to over 12 metres in height and 7 metres in diameter, with walls that tapered slightly outward toward the top.

The craftsmanship of these towers, especially those built with finely cut stones (ashlars), showed a high level of engineering and stonework skill. 

Oriented with a single small opening toward the east, the tombs suggested that the Colla observed solar cycles and associated rebirth with the rising sun.

Archaeological excavations revealed that the towers had contained the burials of multiple individuals, often placed in seated or flexed positions and accompanied by textiles, ceramics, and offerings of gold, silver, or bronze.

These items indicated the high status of the deceased and suggested continued honouring of ancestors through ritual activity at the tombs. 

Unlike earlier Andean burial practices, which involved subterranean graves or smaller chambers, the vertical construction of the chullpas likely showed political authority and a belief in spiritual elevation.

Towers positioned in visible locations communicated social rank, reinforced family lineage, and indicated it as a sacred place.

Since the towers varied in their dimensions and decorative approach, and since some displayed markedly superior workmanship, the builders likely used them to distinguish degrees of wealth and status among the Colla elite.

One of the most finely crafted examples, known as the Lizard Chullpa, featured detailed stone carvings that included a lizard design, which gave the structure its name.

While archaeologists identified serpent carvings elsewhere on the site, the Lizard Chullpa itself remained primarily associated with the lizard figure. 

However, some towers remained incomplete, with loose stones or half-finished foundations indicating that construction had halted suddenly, and this interruption coincided with the period of Inca conquest, which brought new building practices and central control over local rituals.

Although the Inca borrowed architectural methods from conquered peoples, and this included ashlar masonry, most scholars believed the Sillustani towers had predated the conquest and had originated under Colla direction.

The burial structures therefore served as direct evidence of Colla beliefs, hierarchy, and responses to the challenges of their time. 

Aside from the towers themselves, Sillustani produced a range of archaeological discoveries that helped deepen understanding of the site’s ritual importance.

Carved animal motifs, such as serpents and lizards, appear on the outer surfaces of several chullpas, and these designs may have served as guardian spirits or may have shown cosmological themes in Colla mythology.

Some scholars linked these symbols to regional deities such as Tunupa, a mythological figure in Aymara and other Andean traditions who associated with volcanoes, transformation, and ancestral power.

Researchers also found carved niches and stone altars near the towers, which likely served as places for offerings or ancestral ceremonies. 

At several locations, carved cylindrical stones that look like umbilical cords appear beside the towers.

Some archaeologists had proposed that these served as connections between the ancestors and the sacred earth, showing that people believed the dead still affected the land. 

In addition to the funerary towers, the site included evidence of residential buildings and communal spaces where families gathered for seasonal rituals or feasts.

Nearby hearths, cooking vessels, and refuse deposits suggest that ritual activity at Sillustani extended beyond burial into broader patterns of community memory and social ties.

Some pottery fragments show geometric designs that match those found at other Colla sites, which connected the tombs to a common cultural tradition. 

Local oral traditions, passed down through communities that speak Aymara, kept stories about the towers and the ancestors who lived within them.

These legends describe spirits who inhabit the tombs and who influence the wellbeing of surrounding communities, confirming the site’s sacred status long after its original builders disappeared.

Even under colonial rule, the site continued to be a place of quiet reverence, and today it still attracts both pilgrims and scholars who seek to understand the world that once thrived on the shores of Lake Umayo.