Small but important correction, Sagrada Familia is not a Cathedral but a Basilica. A Cathedral hosts the seat of the bishop. Barcelona already has a Cathedral,

Small but important correction, Sagrada Familia is not a Cathedral but a Basilica. A Cathedral hosts the seat of the bishop. Barcelona already has a Cathedral, located in the old gothic district, between Via Laietana and Sant Jaume Square. AFAIK there are no plans to demote the existing Gothic Cathedral.