From the top of its twenty-five meters, the semaphore of Cap-Ferret (Gironde) watches night and day. It can see up to 50 kilometers away, 360 degrees, from the Atlantic coast inside the basin. Whether they are fishing boats or recreational boaters, the military observe, inform in the event of an accident and assist if necessary. Built at the end of the 19th century, the Sémaphore du Cap-Ferret still belongs to the national navy.