The Polychrome Expansion marks the widespread dispersal of an emblematic ceramic style across much of Amazonia during a period of broad social transformation. Yet the timing and constituent routes for this dispersal are poorly understood, in part due to a lack of dating at many sites. Here, the authors apply computational methods to model the expansion via existing radiocarbon dates, critically examining issues of timing, travel and trade/conflict. The results, they argue, call for a reinterpretation of the Polychrome Expansion as a long-lasting and gradual process that advanced from secondary rivers and spread along main channels, eventually impacting colonial history.

Stretching for 1.5km and consisting of approximately 5200 precisely aligned holes, Monte Sierpe in southern Peru is a remarkable construction that likely dates to at least the Late Intermediate Period (AD 1000–1400) and saw continued use by the Inca (AD 1400–1532). Yet its function remains uncertain. Here, the authors report on new analyses of drone imagery and sediment samples that reveal numerical patterns in layout, potential parallels with Inca knotted-string records and the presence of crops and wild plants. All this, the authors argue, suggests that Monte Sierpe functioned as a local, Indigenous system of accounting and exchange.

Archaeological evidence suggests that the transition to food-producing economies in the Western Valleys of northern Chile led to a decline in foraging in highland areas around AD 650, yet colonial records from the sixteenth and eighteenth centuries attest to the continued existence of foraging groups. Taking the Camarones River Basin as a test case, this study identifies small-scale settlements and hunting installations in upland areas using remote-sensing data. In considering these new data alongside ethnohistorical accounts, the author proposes that foraging endured into the late colonial era, possibly coexisting with herder and agropastoral communities and precipitating tethered settlement patterns.

The nature and extent of the Tiwanaku state expansion in the Andes during the second half of the first millennium AD continues to be debated. Here, the authors report on the recent discovery of an archaeological complex 215km south-east of Tiwanaku, where a large, modular building with an integrated, sunken courtyard strongly resembles a Tiwanaku terraced platform temple and demonstrates substantial state investment. Constructed, the authors argue, to directly control inter-regional traffic and trade between the highlands and the eastern valleys of Cochabamba, the complex represents a gateway node that effectively materialised the power and influence of the Tiwanaku state.

The sacralisation of mountains played an important role in the expansion of the Inca Empire into the south-central Andes during the mid-second millennium AD. Here, the authors compare archaeological material from sacralised mountains in north-western Argentina, highlighting not just the shared attributes of high-altitude sites but also the diversity of ways in which Inca dominion over the mountains could be materialised. Focusing on Mount Inca Viejo, in the Argentine province of Salta, the authors further explore the characterisation of sacred mountains and the significance of mining and mineral acquisition as a motivator for Inca expansion.

This Andean coast research has identified 113-plus geoglyphs spanning the Formative (1800–100 BC) to the Inka period (AD 1470–1532). The project combined digital technology and Remotely Piloted Airborne Systems to locate the sites. The authors also documented examples of ceramics and intricate road systems and suggest that the finds represent meticulously ritualised landscapes.

Archaeological cultures present allegories of ethnic identities across the centuries or millennia but such conceptualisations are necessarily incomplete and lack the resolution to explore transitions between cultures. Here, exploration of the archaeological contexts, production methods, stylistic variation and radiocarbon dating of 20 preserved textile fragments facilitates an examination of cultural change at Huaca del Sol (Huacas de Moche, northern Peru). While occupants of the site experienced many outside cultural influences, including those from the highland Wari Empire, continuity in textile traditions suggests that some sense of Moche identity was maintained through the tenth century and after the perceived end of the Moche culture.

Systematic investigation of caves and rockshelters in Uruguay is revealing the archaeological importance of these sites and their association with earthen mounds. Multiple periods of human occupation at Tamanduá rockshelter are revealed through stratigraphic analysis, and radiocarbon dates suggest recurrent occupation from the Early Holocene up to the historic period.

The Redes Andinas (Andean Networks) project assesses the complexity of ancient road networks in the archaeological record in the Andes, beyond the Inca roads system. A multiscale methodological approach allows us to characterise the transformation and resilience of the road networks over the past millennium, in the context of the 18°South parallel's vertical transect.

This project in southern Chile's Lake Region analysed late Pleistocene human–environment interactions. Two field seasons in 2020 and 2022 provided a new lithic collection dating to around 17 300–12 800 cal BP, which indicates human presence in north-western Patagonia prior to the Younger Dryas period.

Imagery-based survey is capable of producing archaeological datasets that complement those collected through field-based survey methods, widening the scope of analysis beyond regions. The Geospatial Platform for Andean Culture, History and Archaeology (GeoPACHA) enables systematic registry of imagery survey data through a ‘federated’ approach. Using GeoPACHA, teams pursue problem-specific research questions through a common data schema and interface that allows for inter-project comparisons, analyses and syntheses. The authors present an overview of the platform's rationale and functionality, as well as a summary of results from the first survey campaign, which was carried out by six projects distributed across the central Andes, five of which are represented here.

This new project studies the diversity of socioecological niches across the agropastoral transition in the Andes, utilising a multi-isotope approach to track human territories and allocate subsistence tasks. During the agropastoral period, we discriminate different diachronic niches with varying extents of maize farming and altitudinal mobility.

Research carried out in the Carangas region of highland Bolivia has identified a surprising concentration of pre-Hispanic religious sites, which are linked both to ancient Andean cults of wak'a (sacred mountains, tutelary hills and mummified ancestors) and to the Incan settlement of the region. Of these sites, one ceremonial centre stands out for its unprecedented characteristics for the Andes.