A headland this prominent does real work on a map. Cap de la Nau marks the southern limit of the Gulf of Valencia, the great curve of coast that opens to the north, and it closes that gulf like a full stop. It belongs to Xabia, in the comarca of Marina Alta, and it is the sort of place that defines a region by its edges: everything in the Valencian Community lies to the west of this rock. Ships rounding it feel the character of the coast change, from the sheltered sweep of the gulf to the more exposed water that runs south toward Alicante. The cape points across the water toward Formentera, the low-lying southernmost of the Balearic Islands, as if marking the shortest line between the mainland and the archipelago.

The cape is rocky, steep, and built almost entirely of limestone, the same pale stone that shapes so much of this coastline into cliffs and coves. It rises abruptly from the Mediterranean, and it is easy to understand how it earned its maritime name; approached under sail, the headland's profile suggests the high bow of a vessel driving through the swell. In English the same feature is sometimes called Cape Nao, in Spanish Cabo de la Nao, but all three names carry the same image, a ship rendered in stone, permanently anchored at the corner of Spain.

The most remarkable thing about Cap de la Nau hides where most visitors never see it. Directly beneath the headland opens a large sea cave, the Cova dels Orgues, the Cave of the Organs, which can be reached only from the water. No path descends to it; to enter, you come by boat or kayak, sliding out of the sunlight into a chamber of dripping limestone where the sea breathes against the walls. Caves like this shape the whole submarine face of the cape, a hidden architecture carved patiently by the same Mediterranean that laps so calmly at the surface. On calm days small boats nose in under the cliffs to explore it, gliding into a shadowed chamber where the light turns green and the swell echoes off the stone.

Cap de la Nau does not stand in isolation but anchors one of the most dramatic stretches of the Costa Blanca. To the south the cliffs of Benitatxell fall sheer toward hidden coves reachable only on foot or by sea; to the north the coast breaks into the bays and headlands of Xabia. This is a shoreline of white limestone and deep blue water, of pine clinging to rock and the constant presence of the Balearic horizon. The cape is its pivot, the point on which the whole coastline turns from north-facing gulf to open eastern sea.

Crowning the headland, 122 metres above the waves, stands the Cap de la Nau lighthouse, still doing the job the cape has always demanded of anyone who lived near it: watching the sea and warning those upon it. From the terrace beside the light the view runs down cliffs that fall dizzyingly to the water and out across the strait toward the Balearics. On a fine evening it is one of the great vantage points of the Costa Blanca, the eastern extremity of mainland Spain, with the whole Mediterranean opening ahead. Few places on the Spanish coast feel so much like an ending and a beginning at once.