The Basilique-cathédrale Notre-Dame de la Treille is a prominent Roman Catholic church located in Lille, France. It was built to honor the Virgin Mary and serves as the seat of the Archdiocese of Lille. Construction began in the 19th century and continued into the 21st century, showcasing a blend of architectural styles, including Gothic and Neo-Gothic elements. The basilica is known for its striking façade, which features a large rose window and a modern glass front completed in 1999. Inside, visitors can find beautiful stained glass windows and intricate sculptures, making it a significant cultural and religious landmark in the region.