Abstract: The two ceremonial centres of Tulán-5 and Tulán-54, in the heart of one of the world’s most arid deserts, are an unparalleled example in the Andean area. Tulán-5, which dates to the Late Archaic period, is in fact a unique case in this area of a megalithic ceremonial centre erected by non-sedentary hunter-gatherer communities. It represents as a onemillennium- more prototype of Tulán-54. Tulán-54 dates from the early phase of the Formative Period, and attests to the development of camelid breeding and horticulture. This ceremonial centre also is unique from an architectural perspective with its central half-buried megalithic enclosure, partitioned by walls converging towards a central cell, and its burials of new-born babies accompanied by rich offerings. Data from the settlements and burials do not support the idea of monumentalism associated with stratified societies, where ritual elites would monopolise wealth. On the contrary, they lead us to turn to other early forms of non-funerary monumentalism, megalithic or not, dating from the beginning of the Neolithic process, in which elites would be organised corporately, with no personal accumulation of wealth. Keywords: Atacama, Chili, Recent Archaic, Formative, ceremonial centres, hunter-gatherers,