Tevennec lighthouse, Stone lighthouse on Île-de-Sein, France

Tevennec lighthouse is a cylindrical stone tower painted white, topped by a flat dark lantern room ringed by a small white gallery. A low white rectangular building with a flat roof is attached to one side of its base. The whole structure stands directly on dark, reddish-brown jagged rock in the north part of the Raz de Sein, off the Pointe du Van.

The Tévennec light was first activated in 1875, one of two sector lights meant to mark the safe channel of the Raz de Sein at night; La Vieille followed in 1887. The 1873 plan of the Commission des Phares chose a sector light on the Tévennec rock rather than a new long-range tower. It was automated in 1910 and listed as a monument historique on 31 December 2015.

The rock's name appears as "le Grand Stevennet" on 18th-century charts and as "Le Tévennec" on Beautemps-Beaupré's 19th-century maps. Breton tradition makes it the point where the Ankou, the maritime death figure, glides through the Raz de Sein in the Bag noz, the funeral boat carrying the souls of those lost at sea; sailors who saw it were said to die within the year.

The tower stands on the Tévennec rock at the northern exit of the raz de Sein, off the pointe du Van; no landing is possible on the rock, so the lighthouse is seen from a boat or from the Île de Sein and the mainland coast. The passage is safest when the current and wind run the same way; with a coefficient above 100 the current reaches 6 to 7 knots, and in heavy weather no crossing is attempted.

In 1893 an exorcist priest came to the rock and a cross was set up on its summit; it stood for over a century until the 2009 storm loosened it and it disappeared. In 2012 the Société Nationale pour le patrimoine des Phares et Balises replaced it with a new wrought-iron cross. In the 1990s an explanation for the noises was put forward: waves sometimes funnel into a fissure and pass right through the rock, producing dull sounds.