Ar-Men Lighthouse

Constructed from granite, the Ar-Men lighthouse stands 36 meters tall with a focal height of 29 meters. Its cylindrical tower, painted black, is topped by a lantern and gallery, and incorporates keeper's quarters. Construction began in 1867 on a rock 8 kilometers west of Île de Sein, and after two decades of difficult work, it was first lit in 1881. Further improvements and structural reinforcement continued for another twenty years. The lighthouse was automated in April 1990 and maintains an operational status. Its light casts a white beam, producing three flashes every 20 seconds, with a geographic range of 15.1 nautical miles.

Why it matters: Ar-Men marks the westernmost point of the Chaussée de Sein, a significant hazard in the Atlantic Ocean. Its construction is considered an extraordinary feat of 19th-century engineering due to the extreme conditions faced by the builders.