Visitable mine of El Alto Tomillo Activity · Barruelo de Santullán, Montaña Palentina, Palencia Image of Barruelo de Santullán, not of the place itself. A kilometre from the urban centre one can walk through a coal gallery fitted out for a guided visit of some forty-five minutes, in which former miners explain the evolution of work underground. Photo: MiguelAlanCS (CC BY-SA 4.0) What to see and do in Barruelo de Santullán