Reserva natural de las Islas Columbretes

Reserva natural de las Islas Columbretes is a marine nature reserve off the coast of Castelló de la Plana in Spain, protecting four volcanic island clusters 48 kilometers from shore. The reserve covers both underwater ecosystems and terrestrial zones, with Illa Grossa being the only island where visitors may go ashore.

Greek and Roman sailors called these islands Ophiusa and Colubraria because of the many snakes living on the volcanic terrain. The lighthouse on Illa Grossa was built between 1856 and 1860 to guide ships along this remote stretch of coast.

The name derives from the Latin word for snake, reflecting creatures that once roamed the islands before removal in the 1800s. Visitors today can explore the old lighthouse keeper's quarters on Illa Grossa, now used for educational programs about marine conservation.

Access to the islands requires permission from reserve staff, which can be arranged through the visitor center at the Castellón de la Plana Planetarium. Daily visitor numbers are limited, so it is best to request authorization well in advance, especially during summer months.

The reserve protects the Columbretes lizard, found nowhere else in the world. The waters around the archipelago serve as nesting grounds for Audouin's gull, a rare seabird that breeds in only a handful of Mediterranean colonies.