Centenary oak wood of Guardo Nature · Guardo, Alto Carrión, Palencia Image of Guardo, not of the place itself. A stand of centuries-old oaks considered one of the best preserved in Spain, extending between 1,100 and 1,800 metres of the municipal district and threatened for decades by the advance of open-cast mining. Photo: Alejandro Polanco (CC BY 3.0) What to see and do in Guardo