Basilica of Our Lady of Mercy

Basílica de la Mercè is dedicated to Our Lady of Mercy, declared co-patron saint of Barcelona in the 17th century after she was credited with saving the city from a plague of locusts, and she's still honored every September with La Mercè, Barcelona's largest annual festival of fire runs, human towers, and concerts across the city. The Baroque interior, more restrained than the exterior's imposing facade, houses the venerated statue of the Virgin at its center, and the church remains an active place of worship rather than a museum piece, with regular Mass and occasional special events drawing crowds.

Reviewers note it's easy to wander in while passing through the harbor-adjacent streets near Port Vell. It's a worthwhile stop for those interested in the religious traditions behind Barcelona's biggest annual celebration, especially if visiting in September.