There was a time when two popes vied for Christendom, and one of them reigned here. Peñíscola, on Spain's Levante coast, juts out into the Mediterranean at the end of a strip of sand: a fortified rock crowned by a castle, encircled by ramparts and linked to the mainland by an isthmus the sea has sometimes covered over the centuries. The silhouette is recognizable from afar, and it lives up to its promise up close.

From the quay to the old town

Passengers disembark near the fishing port, right at the foot of the promontory. Everything is then done on foot: the old town must be earned through sloping lanes, cobbled and whitewashed, where balconies overflow with geraniums. You pass through the Portal de Sant Pere or the Portal Fosc, vaulted passageways set into the walls, and climb unhurriedly, stopping at the viewpoints that open up between the houses. Wear comfortable shoes: the cobblestones, polished by the centuries, can be slippery when you head down too quickly.

The castle of Papa Luna

At the summit, the fortress bears witness to an unusual history. Built by the Knights Templar at the turn of the 14th century on the remains of an Arab citadel, it became, from 1415 to 1423, the residence of Benedict XIII, the "Papa Luna," an Avignon pope who took refuge here during the Western Schism. From its terraces, the view takes in the sea on three sides, the rooftops of the town and the long curve of the coast. The vaulted halls, the parade ground and the former outbuildings can be explored in about an hour.

Ramparts, cannons and the Bufador

Around the castle, the 16th-century fortifications, reinforced under Philip II, offer a wall walk from which cannons still point toward the horizon. On the way down, listen closely near the Bufador: this natural chimney carved into the rock connects with the sea, and in heavy swells, the water breathes noisily beneath passers-by's feet. Children love it, and so do photographers.

A film set

This stone theatre has not escaped the cameras. In 1961, Charlton Heston filmed El Cid here; more recently, the series Game of Thrones set the city of Meereen here. Wandering the alleyways, you understand the location scouts' choice: every corner of wall seems ready for the next scene. The small Sea Museum, housed in an old building in the upper town, tells the long maritime history of the peninsula.

The beach and the fish auction

Below, two worlds share the shoreline. To the north, a sandy beach stretches for more than five kilometres along the modern resort, perfect for a swim or a walk with your feet in the water. To the south, the fishing port carries on at its own pace: in the late afternoon, the trawlers return and unload their crates amid the cries of gulls, a free and unchanging spectacle of the Spanish Mediterranean. Farther south, the Serra d'Irta unfolds one of the last wild coastlines in the region, a nature park where pebble coves and rosemary-covered hills follow one another without a single building.

The rock in the rear-view mirror

You head back down to the quay through the same lanes, transformed in the fading light, treating yourself along the way to a glass of ice-cold orxata, the emblematic drink of the Valencia region. Peñíscola belongs to that family of ports of call where history is not locked away in a museum: you walk right through it, literally, from the first step to the last. The ship pulls away, the castle shrinks on its rock, and everyone keeps the same image in mind, that of a fortress that, six hundred years later, still refuses to leave the sea.