The Sima de los Huesos Nature · Ibeas de Juarros, Burgos (Alfoz), Burgos Image of Ibeas de Juarros, not of the place itself. At the bottom of a thirteen-metre shaft, at the end of a gallery of the Cueva Mayor, appeared the largest accumulation of human fossils in the world: thousands of remains of Homo heidelbergensis, among them the so-called Skull 5. Photo: LBM1948 (CC BY-SA 4.0) What to see and do in Ibeas de Juarros