Caves and potholes in Castellar del Vallès

Castellar del Vallès, on the banks of the Ripoll river and with a rich industrial textile past, stretches across the Vallès Occidental up to the massif of Sant Llorenç del Munt. The conglomerate rock that characterizes this neighboring massif produces a catalogue of cavities of its own, in a municipality that combines its urban core with largely untransformed mountain areas.