The carnival and Corpus Christi born from a papal bull Activity · Palacios de la Sierra, Sierra de la Demanda, Burgos Image of Palacios de la Sierra, not of the place itself. A papal bull of 1661 fixed the village's two great festivals: the carnival joined to the feast of the Blessed Sacrament on Quinquagesima Sunday, and Corpus with decorated altars and children who scatter petals in its path. 1661 Photo: LBM1948 (CC BY-SA 4.0) What to see and do in Palacios de la Sierra