A blockhouse built by Nazi Germany in 1943 as part of the Atlantic Wall has collapsed on Horizon Beach in Lège-Cap-Ferret due to coastal erosion. The structure, known as Ar 36 in the Arcachon sector, was originally built to monitor the coastline and repel Allied forces during World War II. After nearly 80 years, the blockhouse fell as the sandy dune beneath it eroded from constant wave action and winter storms. This erosion weakened the dune's base, causing the blockhouse to lose its support and ultimately collapse. According to the deputy mayor for urban planning, the dune's foundation was gradually worn away by waves and storms, leading to sand slides that removed the blockhouse’s support. The mayor of Lège-Cap-Ferret added that this is not an isolated case—other blockhouses in the area have also been submerged more than 15 meters below sea level in the Arcachon Basin. These historical structures are now largely hidden beneath the water, showing how dramatically the coastline has changed over time. The collapse of the blockhouse underscores the growing problem of coastal erosion, which has become a major concern for communities along the French coast. In response, an amendment has been approved for the 2026 financial law, establishing a national fund to combat erosion. This fund could be partially financed by a tax on tourist rental properties, signaling a shift from local to national attention on the issue. The blockhouse's fall is a visible reminder of how the coastline has receded over the decades. Many structures that were once safely inland are now exposed to the sea, demonstrating the slow but persistent impact of erosion. This event raises important questions about how to manage and protect coastlines in the future, especially as erosion continues to accelerate due to climate change and rising sea levels.