The architecture of the main lighthouse, completed in 1902, is a marvel of resilience and beauty. Its exterior is constructed from massive blocks of local granite and kersantite, a fine-grained stone favored by Breton sculptors for its durability against the salt and wind. However, the real secret is tucked away inside. The interior walls are lined with 12,500 opaline glass tiles, crafted by the famous Saint-Gobain factory. These vibrant blue-azure tiles were not just for show; they protected the masonry from humidity and helped bounce the light throughout the core of the tower. To reach the top, you must ascend a suspended granite staircase of 397 steps, each carved from a single piece of stone.