LAUSR

Abstract The so-called Basque crossroads constitutes a small region disposed on both slopes of the western Pyrenees, with one part on the north of the Iberian Peninsula and another, on the southwest of present-day France. Throughout the Pleistocene, it has been the main path for human populations to transit between the Iberian Peninsula and the rest of Europe, given that the orography and the presence of a vast frozen steppe in the current region of the Landes set the human mobility through known corridors. On the other hand, in the last two decades, it has been proven that this is the only area of the Cantabrian region with high permeability to other regions of the Iberian Peninsula, such as the Ebro Valley, or the Castile northern Plateau. Both findings require to modify the previous vision of the Upper Palaeolithic in the area. From a geographical and palaeoenvironmental point of view, this characterisation as a crossroads region has relevant implications. Despite its small dimensions, there are numerous climatic nuances between very close areas in space. All this variability increases in exponential terms when we also value a broad range time scale.