Saint-Julien Cathedral is a Roman Catholic cathedral located in Le Mans, France. It is known for its stunning Gothic architecture and beautiful stained glass windows, some dating back to the 12th century. The cathedral serves as the seat of the Bishop of Le Mans and is a significant historical and religious site. Construction of the cathedral began in the 11th century and continued for several centuries, resulting in a blend of architectural styles. The cathedral is also famous for its impressive organ and the remarkable crypt that houses ancient relics. It is a popular destination for both tourists and pilgrims.