BARCELONA, Spain — BARCELONA, Spain (AP) — Pope Leo XIV will bridge 1,000 years of church history Wednesday, visiting a medieval monastery on a mountaintop that local Catholics consider sacred and then celebrating Mass at Barcelona’s famous Sagrada Familia Basilica.

Montserrat, a healthy drive from the city followed by a steep ascent, is dear to many of the Catalan people in northeastern Spain. Annually, 2 million people travel to the complex that includes an 11th-century Benedictine abbey as well as a 16th-century basilica. Its Black Madonna statue, which studies show originally was white but turned dark by centuries of smoke and incense before being painted black, is widely revered.

But for many Catholics watching from afar — and especially non-Catholics — the highlight of the Chicago-born pope’s seven-day trip to Spain will be his evening Mass at the Sagrada Familia — the Basilica of the Holy Family — commemorating the centennial of the death of its architect, Antoni Gaudí. Leo will speak almost exclusively Spanish on the trip, with some comments in Catalan.

The visit 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 more a magnet for tourists than believers. Yet the two sites share a connection even some locals don’t know.

The Sagrada Familia fuses the universal language of nature — trees, birds, reptiles, cornucopias of fruit — with scenes from Christ’s life. Beyond that unique aesthetic, its allure stems from allowing visitors to bear witness to a great church’s ongoing construction.

That began 144 years ago, with the first cornerstone laid in 1882 during the pontificate of Leo’s namesake, Pope Leo XIII.

Its claim to “the new” is what sets Gaudí’s masterpiece apart from Europe’s other cathedrals and why it has captivated millions. Leo’s Mass is an opportunity to link him with this breathtaking place of worship.

“Its stones and stained glass speak of the possibility of conjuring up 2,000 years of Christian history from a modern and even postmodern view,” Ferran Sáez, professor of humanities at Barcelona’s University of Ramón Llull, told The Associated Press. “It is a building that expresses very complex ideas while coming across as comprehensible for anyone who is receptive, whether they are Christian or not.”

The Sagrada Familia is an international sensation, featuring on virtually any self-respecting globetrotter’s bucket list. Foreigners account for 90% of its visitors, whose entrance fees fund its construction, and more Americans visit than Spaniards, according to the basilica.

While there aren’t statistics on visitors’ average age, it is hugely popular among adolescents and twentysomethings. That’s in stark contrast to the graying parishioners at most Spanish churches at a moment the Catholic Church strives to engage with and remain relevant to youth.

The basilica’s latest superlative — world’s tallest church, with its recently raised Tower of Jesus Christ — has made it an even greater beacon.

The Sagrada Familia is a global pulpit, but it’s set in a country where Christianity is receding. Spain underwent a religious crisis in the late 20th century during its return to democracy. Just over half of Spaniards polled by the state opinion agency in 2024 self-identified as Catholics, but only about 1 in 5 called themselves practicing Catholics.

And Catalonia is one of Spain’s most secular provinces, Sáez said.

Catalonia’s Catholics are reserved in their practice, without flamboyant Easter Week processions like those in Seville and other Spanish cities.

The force of their faith rests in its holy places: the Sagrada Familia, the Poblet monastery and the Romanesque churches dotting the foothills of the Pyrenees. And, above all, in Montserrat, where pilgrims arrive by bus, cable car, cog railway and strenuous trails.

“It is home to our most beloved representation of Mary, the Black Madonna,” Catalan theologian Francesc Torralba told AP. “Many Catalans pray to her and feel close to her in times of need. Montserrat is a key to our culture, as well as our efforts to maintain our language and our traditions.”

While Montserrat is the region’s religious epicenter, its faith is “culturally expressed in its artistic creations” like the Sagrada Familia, he added.

And it’s that unbridled and unique artistry that draws so many visitors. Many Barcelona residents feel the Sagrada Familia’s fame has driven some of overtourism’s worst ills. Tour buses flood the area with day-trippers from cruise ships, and streets facing the church are full of fast food restaurants and souvenir shops. Protesters who squirted tourists with water guns last year were planning to reach the Sagrada Familia until police stopped them.

“Where there are two people (tourists and locals), there can be friction, and that happens in the best marriages,” the Sagrada Familia’s rector, the Rev. Josep Turull, told AP. “So we try, just like with a marriage, for these small crises to be growing pains, and that’s why we try to not just welcome pilgrims and tourists but also make sure that our parishioners feel that this is their basilica.”

Leo could bring even more tourists. Pope Benedict XVI’s consecration to make it an operating basilica in 2010 boosted visits from about 3 million a year to nearly 5 million in 2025, according to Xavier Martínez, the CEO of the Sagrada Familia’s construction project.

“I believe that on June 10 we will experience something similar to what we saw in 2010,” Martínez said. “At that time, the world discovered the interior of the Sagrada Familia. Now the world will discover the towers of the Sagrada Familia.”

Tour guide and historian Mònica Santín has seen the Sagrada Familia’s stunning power for believers and nonbelievers alike; some even weep upon crossing the church’s threshold. As personally fulfilling as it is to help tourists achieve these life-changing moments, she is concerned Leo’s Mass could drive tourism to levels that are unsustainable for the community.

Santín has reserved her spot to see Leo in person, but it won’t be at the basilica. She will instead make the journey to the Montserrat monastery.

Santín’s grandmother made the same pilgrimage, walking barefoot to a mountainside cave where legend has it shepherds discovered the Black Madonna statue and prayed for protection for her husband during the Spanish Civil War. Today, Santín wears the ring her grandmother gave her.

“I don’t know how it doesn’t fall apart,” Santín said, gently touching her ring, with its profile of the Virgin of Montserrat, the patron saint of Catalonia, barely visible after so many years.

And she notes that Montserrat and the Sagrada Familia have a shared, but little-known, connection.

A young Gaudí apprenticed with an architect building the mountaintop chapel for the Virgin of Montserrat, according to Santín, who is researching her doctoral thesis on the architect at Barcelona’s ISCREB theology school. That same architect was originally hired to build the Sagrada Familia, but material costs made his neo-Gothic proposal inviable and the commission went to Gaudí. As part of his radical design, he introduced elements of the mountain.

Even the basilica’s sandcastle-like towers resemble the spirelike rock formations that every Catalan can identify as jutting from Montserrat.

“Montserrat is our holy mountain,” Santín said. “The Sagrada Familia is like a Montserrat in the middle of the city.”