The explosives factory of Guardo Historical milestone · Guardo, Alto Carrión, Palencia Between 1942 and 2008 a large chemical plant of Unión Explosivos Río Tinto operated at Guardo which, along with anthracite and the coal railway from La Robla to Bilbao, made the town the largest industrial centre of the Palencia mountains. 1942-2008 Photo: Alejandro Polanco (CC BY 3.0) What to see and do in Guardo