New Delhi, June 11 -- Pope Leo XIV celebrated the Sagrada Familia Basilica as a masterpiece of "stones, colors and light," as he marked the centenary of the death of its architect, Antoni Gaudi, with a Mass on Wednesday to inaugurate its final soaring sandcastle spire.

Leo called Gaudi's unfinished temple, one of the world's most visited monuments, a "sign of unity and harmony for all of Spain," an ongoing building project like the lifelong journey all Christians make to find God.

"We are all the living stones of this edifice," Leo said from the altar of the basilica, with Spanish King Felipe VI and Queen Letizia sitting to his side and a hundreds-strong choir filling the basilica with song.

The service was the highlight of Leo's weekl...