Valença

Valenca is two towns in one. Below the walls is a modern commercial centre, unremarkable. Above, within the massive star-shaped Fortaleza, is a complete walled town — cobbled streets, churches, shops, restaurants, and views across the Rio Minho to Tui in Spain.

The fortress is actually two forts side by side, built in the Vauban style of military architecture that dominated European fortification design in the 17th and 18th centuries. The walls are enormously thick and the layout is designed so that every angle is covered by crossfire from another bastion.

Enter the citadel from its southern door (near the Albergue Sao Teotonio, along the Avenida dos Bombeiros — this approach is recommended). Inside the walls: the Capilla da Misericordia with its polychromatic retablo; the Igreja de Santa Maria dos Anjos; the Igreja da Colegiada de Santo Estevao; a 1st-century Roman miliario; the statue of Sao Teotonio, Portugal's first canonised saint; and the Capilla do Bom Jesus. Walk the perimeter walls for views of the river, Tui's cathedral on the far bank, and the Ponte Internacional connecting the two countries.

The shops inside and around the fortress sell cheap towels, linens, and household goods — a cross-border trade that has attracted Spanish shoppers for decades. The commercial focus can feel at odds with the military grandeur, but there it is.

Leave Valenca through the citadel or along the Avenida de Espanha, crossing the Ponte Internacional into Spain. Change your watch — Spain is one hour ahead.