Some 40km north of Vila Real – and best approached by car along the road that hugs the Guadiana River – is the extremely attractive border village of ALCOUTIM. It has a long history as a river port, dominated in turn by Greeks, Romans and Arabs who all fortified the heights with various structures; the castle (daily 9am–7pm, closes 5.30pm from Oct–March; €2.50) dates from the fourteenth century and offers fine views over the river. The entrance fee includes access to a small archeological museum by the main gates, which traces the history of the castle, its active service in various battles and the remnants of earlier structures on the site. From the castle, cobbled backstreets lead down to the small main square, below which is the appealing riverfront. Currents are too strong for safe swimming, but you can take a boat across the river (around €1.50 single) to the Spanish village of Sanlúcar, a mirror image of Alcoutim, with its own ruined castle; or swim at the river beach (praia fluvial) in a small tributary off the Mértola road.