Semaphore of Pointe du Grouin

Very nice hike, for the history of the semaphore:
"It is not a lighthouse but a semaphore: an old communication relay, using 92 flags of various shapes and colors, hoisted to communicate with other semaphores. It was built in 1861. In the 20th century, this system was replaced by the telegraph (then the telephone, then the internet...) it became an observation post for offshore boats. But it was disarmed by the French Navy in 1999, as were 20% of observation semaphores. Other semaphores are indeed capable of observing maritime traffic with more powerful radars, but without "visual" observation. The building, which looks like a ship, with its large glass walkway, antennas and radars, housed two official apartments. Today it is sometimes used as an exhibition hall."
Credit Patrick Palmas from ©Seevisit

Offshore surveillance lookout. Unfortunately closed for a good part of the year

The views are absolutely worth seeing! After the tour, it's worth following the coastal path and visiting one or all of the beaches...