The study of traditional views about the structure and the workings of the cosmos remains a fertile field of exploration, as numerous apparently global motifs have not been recognised, let alone carefully documented or explained. One traditional cosmological idea whose practically universal geographic distribution has rarely been appreciated concerns the physical constitution of the sky. According to this extremely widespread motif, the sky is an impenetrable “sheet” or “dome” formed of a solid material, such as rock or metal, but contains (...) one or more holes, which facilitate cosmic traffic.1 The Maya of Chumayel, Yucatán, for instance, acknowledged the existence of hol caan or “the hole in the sky.”2 In a .. (shrink)