The CENIEH has participated in the study of the prints of bare feet found at the Sala y Galerías de las Huellas site in the Ojo Guareña Karst Complex (Burgos), which are the marks left in a soft floor sediment of an exploration by a small group of people between 4600 and 4200 years ago. Dating carried out in the access galleries to this site has documented intensive human traffic during the Neolithic, Mesolithic and Upper Paleolithic, confirming reiterated visits to this great cave complex throughout prehistory.