PHOTO BY HUCK BEARD

If it weren’t for the masterpieces surrounding you, St. Nicholas would be relatively small. At its deepest, the church — which is still active and celebrates its 125th anniversary this year — fits just 13 rows of pews; compared to some of the architectural marvels in Pittsburgh, it’s a humbly sized house of worship.

The artwork, however, makes it feel massive.

PHOTO BY HUCK BEARD

The Croatian-born artist Maximilian “Maxo” Vanka immigrated to America in 1934; the following year, his work was exhibited in Oakland. Among the impressed art lovers was the Rev. Albert Zagar of St. Nicholas, who wasn’t too fond of the bare, white walls of his church. Father Zagar and members of his flock asked Vanka to paint murals in Millvale; in 1937, he obliged, adding more works in 1941 and ’51.

The results are stunning, mixing religious iconography with scenes of a world at war. In certain depictions, the immigrant experience is brought to life; in others, soldiers in gas masks dominate the scene. Even traditional images have jarring details; “Crucifixion” includes skeletal saints rising from the ground.

PHOTO BY HUCK BEARD

Public tours of the murals are offered Mondays, Thursdays and Saturdays. (Advance registration is recommended for all tours and required on Mondays and Thursdays.) When you visit the church at 24 Maryland Ave., you’ll be given an hourlong history of the church, the artist and the murals — then invited to study the details that cover the building.

The collision of classic imagery with then-contemporary themes is shaking. And perhaps “then-contemporary” is too limiting; “The Capitalist,” in which a ghoulish man ignores both his servant and a beggar at his feet while studying a stock report, might have been painted yesterday.

“THE CAPITALIST” | PHOTO BY HUCK BEARD

It takes a great deal of work to keep those details intact. Fortunately, painstaking preservation efforts by the Society to Preserve the Millvale Murals of Maxo Vanka (which also administers the tours and events) are ongoing and can be observed by visitors; these are works that are painted directly on the church walls, so they can never be removed or exhibited anywhere else.

To see them, you’ll have to visit St. Nicholas. That’s a good thing; these murals are intractably of this place, and the experience should be a pilgrimage.