The picturesque ruins of Castro Laboreiro's 16th-century castle, built in 1505 on the foundations of a 12th-century Moorish castle, are easily accessible from town via this straightforward 1.6km loop (one hour). Leave the main road just east of the Miradouro do Castelo hotel in the town centre and head toward the massive rocky outcrop looming just south of you.
Following signs marked 'Accesso Sul', you'll soon climb to the castle's southern end and enter through an arched stone gateway with green wooden doors. Little of the original castro remains beyond the bases of a few massive granite external walls and the foundations of a square stone tower, but the mountain perspectives from within are magnificent. Exit the opposite (northern) end of the castle and follow the stone-cut steps and metal railings down to loop back to your starting point.