On the northwest side of Alcántara, a magnificent 2nd-century Roman bridge – 204m long, 61m high, with six arches and much reinforced over the centuries – spans the RÃo Tajo below a huge dam retaining the Embalse de Alcántara. The restorations may have dulled the bridge's obvious antiquity but it's still a stirring sight. From the bridge, a beautiful 20km walking circuit follows the river then loops up into the hills via a village and a prehistoric menhir.
Spot rare birds of prey and black storks along the way.
