The Îles Sanguinaires take their name from the crimson light that ignites their granite cliffs each evening, a phenomenon caused by the iron oxide in the rock reacting with low-angle sun. Four islands—Mezu Mare, dei Corvi, Cala d'Alga, and Porri—form a protected archipelago three nautical miles west of Ajaccio, visible from Pointe de la Parata but inaccessible except by boat. Alphonse Daudet spent three months in the Genoese tower on Mezu Mare in 1862 and later memorialized the isolation in his short story collection, describing the keeper's solitary existence among seabirds and shipwrecks. Today the archipelago serves as a protected nature reserve under French coastal law. Boat departures from Ajaccio's main port operate year-round, with the heaviest traffic concentrated between May and September when the tramontane winds calm and the Mediterranean reaches 24 degrees Celsius. The Genoese tower, constructed in 1608 as part of a defensive chain along Corsica's western coast, remains the only structure on Mezu Mare; the lighthouse adjacent to it was automated in 1985. Puffins, Audouin's gulls, and European shags nest on the cliffs between March and July, prompting seasonal landing restrictions to protect breeding colonies. The îles sanguinaires depuis ajaccio route follows the same channel used by Genoese trading galleys in the sixteenth century, skirting the Pointe de la Parata headland before turning southwest into open water. Most operators offer evening departures timed to the sunset window, which shifts from 20:45 in June to 18:30 in September. The granite changes color in stages—pale rose at 19:00, deep amber by 19:30, then the namesake blood-red in the final ten minutes before the sun drops below the horizon. Daudet called it "a chromatic violence that makes the sea look black by contrast," a description that still holds. The protected status means no commercial development; what visitors see today is geologically identical to what Napoleon observed as a child in Ajaccio.