Marvão's natural assets have contributed to the 'uniqueness' of this remote village as perceived by visitors today: (i) as nigh-impregnable 'eagle's nest' fortress - perched high on a granite crag, and bordered on the south and west by the Sever river; (ii) as vital lookout-point towards the Alcántara Bridge ( 70 kilometers away), a wide stretch of the Tagus basin and the Serra de Estrela; (iii) as a gateway to Portugal from Spain via the Porta da Espada ('Sword Gate') mountain pass of the Serra de São Mamede.