EVEN IF you've never heard of the Ukrainian Catholic Cathedral of the Immaculate Conception in Northern Liberties, chances are you've seen it: Its signature golden dome is easy to pick out on the city's skyline.

But the church is much more than a pretty facade - it's one of four major hubs for the Ukrainian Catholic faith in America.

Rev. Ivan Demkiv, who's steered the congregation for more than a decade, explained what happens beneath the church's brilliant dome. (Full disclosure: Demkiv is the father of one of this reporter's college friends.)

Who we are: Demkiv oversees a congregation of about 300 families, some of the roughly 20,000 cultural Ukrainians who live in the greater Philadelphia area.

Because of that substantial population, Immaculate Conception serves as the seat of Ukrainian Catholic Archeparchy of Philadelphia (the church's equivalent to an archdiocese), which governs all of the Ukrainian Catholic archeparchies - there are four, total - in the United States.

"With the new immigration from Ukraine, I see new faces every Sunday," Demkiv said. "People travel from all over: New Jersey, Delaware, even other parts of the U.S. and Canada."

Where we worship: Immaculate Conception's flock gathers in the Cathedral of the Blessed Virgin Mary, a massive edifice built in the Byzantine tradition - it's modeled after the Hagia Sophia basilica in Istanbul, according to Demkiv.

The structure was built from 1963 to 1966 on Franklin Street near 8th Street. Though its iconic dome - covered in gold-infused Venetian glass tiles - is its claim to fame, the cathedral's interior is even more magnificent, featuring rich, colorful mosaics of biblical scenes and hand-painted icons of the faith's saints and prophets.

But, why Northern Liberties?

"After World War II, displaced Ukrainians came here first," Demkiv said. "We've left our mark in this neighborhood. It's our historic place in the city."

What we believe: Immaculate Conception is a Ukrainian Greek Catholic Church, which follows the Eastern Rite of the Catholic faith. In Roman Catholic parlance, the Vatican and the Ukrainian Catholic Church are said to be in "full communion" - meaning the Ukrainian branch is a member of the larger whole, but with its own distinct cultural identity.

The beliefs are the same, but the way they worship differs slightly. For example, Ukrainian Catholics read from the Divine Liturgy of Saint John Chrysostom during services, instead of the Bible. Their churches feature painted icons (detailed portraits of holy figures) instead of the statues commonly found in Roman Catholic churches. And their hymns don't have musical accompaniment - choirs and churchgoers sing without organs or other instruments.

Still, Demkiv said people who grew up Roman Catholic feel at home in his cathedral.

"We get people who aren't Ukrainian all the time," he said. "They like that we're different but still follow what they believe."

And there's no language barrier: Immaculate Conception offers an English vigil every Saturday at 4:30 p.m., in addition to its Ukrainian liturgy on Sundays at 9 a.m.

What we're known for: "Mention the dome, and everyone knows what you're talking about," Demkiv said.

There's good reason for that: It's the third largest dome in the country, after the ones atop the U.S. Capitol and the Basilica of the National Shrine of the Immaculate Conception, both in Washington.

Another source of pride for the church is its replica of the Shroud of Turin - the cloth Jesus was said to have been buried in - which the Philly archbishop brought to his archeparchy in the late 2000s from Italy.

Foreign relations: In recent weeks, Immaculate Conception has become a place of support for the many Philadelphia Ukrainians who have family affected by the unrest currently rocking Kiev, their homeland's capital.

Demkiv, whose father and brother still live in Kiev, said he's fielded countless calls and visits from parishioners worried about the protests.

"It's very difficult. Everybody is worried about the next step," he said. "When they ask me for advice, I tell them to pray, first of all, and then to provide stability however they can to their families."

The church is also collecting donations for aid organizations working to help those displaced by the riots, organized in opposition to the leadership of current President Viktor Yanukovych.

God is . . . "Infinite power. Through him everything came to be," Demkiv said. "It doesn't matter your faith, everyone can feel his guidance in their lives."