The Phare de Cordouan is a historic lighthouse located at the entrance of the Gironde Estuary in France. Built between 1584 and 1611, it is one of the oldest lighthouses still in operation. Standing at 68 meters tall, it features a unique design that combines both a square base and a round tower, making it a remarkable architectural landmark. This lighthouse is often referred to as the "King of Lighthouses" due to its grandeur and significance. It was designated a Monument Historique in 1862 and is recognized for its role in guiding ships safely through the challenging waters of the estuary.