Tower of Sant Miquel Monument · la Roca del Vallès, Vallès Oriental, Barcelona Image of la Roca del Vallès, not of the place itself. Medieval watchtower in the municipality of la Roca del Vallès, declared bien cultural de interés nacional (Catalonia's highest level of heritage protection). Remains survive of a rectangular-plan wall, with an underground chamber inside; the best-preserved stretch is 90 centimetres thick and has two or three arrow slits in two rows, the lower one now below ground level. It is built of rounded stones with a flattened outer face, bonded with lime mortar in regular horizontal courses. It is thought to have served to defend or watch over the Roman road of Parpers, which passed nearby. Photo: Pere López Brosa (CC BY-SA 4.0) What to see and do in la Roca del Vallès