Barredo Pit Monument · Mieres, Caudal, Asturias A mine sunk by Fábrica de Mieres between 1937 and 1941 to a depth of 355 metres, the setting at Christmas 1991 for the sit-in by the union executives against Hunosa's restructuring plan. Flooded since 1997, its water now provides geothermal heating for several buildings in the municipality. Photo: LMLM (CC BY-SA 3.0) What to see and do in Mieres