The Incas carried out some of the most dramatic ceremonies known to us from ancient times. Groups of people walked hundreds of miles across arid and mountainous terrain to perform them on mountains over 20,000 feet high. The most important offerings made during these pilgrimages involved human sacrifices (capacochas). Although Spanish chroniclers wrote about these offerings and the state sponsored processions of which they were a part, their accounts were based on second-hand sources, and the only direct evidence we have of the capacocha sacrifices comes to us from archaeological excavations.Some of the most thoroughly documented of these were undertaken on high mountain summits, here the material evidence has been exceptionally well preserved. In this study we describe the results of research undertaken on Mount Llullaillaco (6,739 m/22,109 feet), which has the world’s highest archaeological site. The types of ruins and artifact assemblages recovered are described and analyzed. By comparing the archaeological evidence with the chroniclers’ accounts and with findings from other mountaintop sites, common patterns are demonstrated; while at the same time previously little known elements contribute to our understanding of key aspects of Inca religion. This study illustrates the importance of archaeological sites being placed within the broader context of physical and sacred features of the natural landscape. 

The exact timing, route, and process of the initial peopling of the Americas remains uncertain despite much research. Archaeological evidence indicates the presence of humans as far as southern Chile by 14.6 thousand years ago (ka), shortly after the Pleistocene ice sheets blocking access from eastern Beringia began to retreat. Genetic estimates of the timing and route of entry have been constrained by the lack of suitable calibration points and low genetic diversity of Native Americans. We sequenced 92 whole mitochondrial genomes from pre-Columbian South American skeletons dating from 8.6 to 0.5 ka, allowing a detailed, temporally calibrated reconstruction of the peopling of the Americas in a Bayesian coalescent analysis. The data suggest that a small population entered the Americas via a coastal route around 16.0 ka, following previous isolation in eastern Beringia for ~2.4 to 9 thousand years after separation from eastern Siberian populations. Following a rapid movement throughout the Americas, limited gene flow in South America resulted in a marked phylogeographic structure of populations, which persisted through time. All of the ancient mitochondrial lineages detected in this study were absent from modern data sets, suggesting a high extinction rate. To investigate this further, we applied a novel principal components multiple logistic regression test to Bayesian serial coalescent simulations. The analysis supported a scenario in which European colonization caused a substantial loss of pre-Columbian lineages.