The fossil tree trunks of Hacinas Nature · Hacinas, Sierra de la Demanda, Burgos Image of Hacinas, not of the place itself. The first remains appeared around 1840 buried among fluvial materials; the first was moved to the village in 1976 and today three petrified trunks of a forest of some hundred and twenty million years ago can be seen. Photo: Ecelan (CC BY-SA 3.0) What to see and do in Hacinas