The cave of El Pendo is a prehistoric cave located in the autonomous community of Cantabria , in Spain . It is included in the list of World Heritage of Unesco since July 2008 , within the site "Cave of Altamira and Paleolithic Cave Art of Northern Spain " (in English , Cave of Altamira and Paleolithic Cave Art of Northern Spain ). 1 It has been the object of numerous archaeological excavations that have revealed the existence in the site of a relevant stratigraphy .