Pope Leo XIV will bridge 1,000 years of church history Wednesday when he visits a medieval monastery on a mountaintop that local Catholics consider sacred and then celebrates Mass at Barcelona’s famous Sagrada Familia Basilica. The Montserrat monastery is dear to many Catalans, a proud people in northeastern Spain, and its Madonna is revered. But most Catholics and nonbelievers will be focused on the pope’s evening Mass at Sagrada Familia to commemorate the centennial of the death of its architect, Antoni Gaudí. Leo’s visit to both sites illustrates his balancing act of upholding centuries-old religious traditions in a country where faith is waning, while reaching a global audience from a basilica that is a magnet for tourists.