At the mouth of the Gironde estuary, where the Atlantic Ocean meets the river, stands the Cordouan lighthouse, a structure that has guided ships for over 400 years. Known as the last inhabited lighthouse in France, it is a world heritage site, recognized by UNESCO in 2021. The lighthouse is part of a vast protected area of 23,582 hectares, with an additional buffer zone, totaling over 163,000 hectares. This area includes the rocky plateau on which the lighthouse is built, a site that was once above sea level but now is mostly submerged except during low tides. The location is both unique and challenging, as it lies in an open sea environment, making it a dangerous place for navigation. The construction of the Cordouan lighthouse began in the early 17th century and took 27 years to complete, during which builders had to work around the tides. The site, once called the "islet of Cordouan," was built on a rocky plateau that was above water at high tide, allowing for construction. Over time, erosion has caused the plateau to submerge, leaving the lighthouse accessible only during low tides. The original structure, the Prince Noir Tower, was later replaced and reinforced in the late 1700s to prevent collapse. A new conical tower was added, preserving parts of the original while strengthening the structure. Today, the role of a lighthouse keeper is far from the solitary image of the past. Modern keepers work in teams, rotating every week or every 15 days. Their duties include maintenance, monitoring the lighthouse systems, and guiding visitors during the warmer months. The lighthouse is open to the public from April to October, welcoming around 24,000 visitors annually, though access is limited due to the site's challenging geography. Despite being fully automated since 2006, the lighthouse continues to have permanent keepers. This is because the site requires ongoing maintenance and a human touch for visitor services, unlike other lighthouses that have been abandoned once automation was possible. Cordouan's designation as a UNESCO world heritage site in 2021 marked a significant milestone for its history. The recognition came nearly four centuries after its construction, highlighting its cultural and historical value. The restoration work, which took over a decade and included nearly 10 million euros in investment, allowed the lighthouse to reopen in 2022, revealing its restored grandeur to visitors. This effort, much like its original construction, was a long and complex process, carried out in workshops before the stones were reassembled on the rocky base, now shaped by the relentless forces of the Atlantic.