For three centuries, red coral from the Tunisian Tabarka was among the Mediterranean's most prized commodities, and the settlement that harvested it, some two thousand people of mostly Genoese origin, grew wealthy on the trade. The Genoese Lomellini family had held the coral concession from the Bey of Tunis since 1542, and over the generations the settlers put down roots, becoming a distinct community that came to be known as Tabarquinos. In 1741 the Bey of Tunis overran the island and enslaved many of its residents, carrying hundreds off in a single stroke. The kings of Spain and Sardinia offered sanctuary to those who escaped and paid ransoms to free those still held. In 1768 Charles III of Spain secured the release of sixty-nine captive families, who were carried by boat to Cartagena that October. Rather than scatter them, the crown gave them an island of their own off Alicante and let them carry their old home's name to it. From 1770 the place was known as Nova Tabarca, New Tabarca.

Charles III did not simply drop the refugees on a barren isle. He ordered it fortified and repopulated, and the military engineer Fernando Méndez Ras drew up a proper walled town: ramparts, bulwarks, warehouses, and barracks, entered through three monumental gates that still stand. One of them, the San Gabriel gate, carries a Latin inscription crediting Charles III with its making. The Governor's House survives, now a hotel; the church of Saints Peter and Paul was finished in 1779; and at the island's edge stands the Torre de San José, a stout three-story watchtower designed by the engineer Baltasar Ricaud around 1790, which later served a grimmer turn as a state prison in the 19th century. In that same century the island's fishing families swelled its population toward a thousand. Today barely fifty people live here year-round, a figure that multiplies tenfold each summer. It is the only inhabited island in the Valencian Community and one of the smallest permanently settled islands in Spain, a grid of low sun-bleached houses ringed by 18th-century walls. No cars disturb it. On foot, the entire island can be circled in under three hours, past the old gates, the lighthouse, and coves of impossibly clear water.

The waters around Tabarca were declared a marine reserve in 1986, the first of its kind in Spain. The distinction was earned. Beneath the surface lies a vast meadow of posidonia seagrass, the largest such prairie in the Spanish Mediterranean and a nursery for astonishing biodiversity. Sea bass, grouper, conger eel, and gilthead shelter in its blades, and an artificial reef laid by the reserve authorities shields the whole system from fishing pressure. The clarity of the water is not an accident but a record: Tabarca was the last place along Spain's Mediterranean coast where the critically endangered Mediterranean monk seal successfully bred, before vanishing from these waters in the 1960s. The EU has since named the island a Zone of Special Protection for Birds.

Geologically, Tabarca is a foundation of volcanic rock overlaid with limestone and later deposits, a hard little platform that the Mediterranean has polished for millennia. Getting there is part of the pleasure. Ferries leave from Santa Pola on the mainland roughly every hour, crossing the same channel the ransomed families sailed two and a half centuries ago. There is no rush once you arrive, because there is nowhere to rush to. You walk, you swim in water the color of green glass, you eat the caldero the islanders make from the day's catch, and you let the pace of a car-free island reset your sense of time.