(From L) Pastor Gregor Hohberg, Rabbi Tovia Ben-Chorin and Imam Kadir Sanci hold bricks as they pose for photographers in the vacant lot where they hope to build a multi-faith prayer building, in Berlin

BERLIN — Christians, Muslims and Jews, all praying under the same roof — that’s the groundbreaking project of a pastor, a rabbi and an imam in Berlin.

Still a sand-strewn vacant construction site, St. Peter’s Square in the center of the German capital will — God willing — by 2018 host a building that’s so unusual it doesn’t have an official term.

Not a church, nor a synagogue, or a mosque as such, but a bit of all three, the center known currently as a “House of Prayer and Learning” will be unlike any other religious venue in the world, its initiators say.

The aim of the 44-million-euro ($60-million) project, whose fundraising kicked off Tuesday but has been several years in the making, is not only to show the importance of multi-faith dialogue but to mirror multi-cultural Berlin.

“It seemed to us that there was a very strong desire for the peaceful coming together of the religions,” said Roland Stolte, one of two Protestant representatives on the board of the association behind the project.

Not by coincidence, it will stand at a location with a strong and long religious significance.

In 2007 archaeological excavations unearthed the foundations of four previous St. Peter’s churches that had stood on the site at different periods since the Middle Ages, Stolte told AFP in an interview.

The last one, which had a striking 100-meter-tall (328-foot) steeple and dated from the mid-19th century, was damaged in World War II and later demolished by the former East German communist state in the early 1960s.

A car park then occupied the site which the city authorities later handed back to the local Protestant community. “We wanted to revive this place, not by building a church again but by constructing a place that says something about the life of religions today in Berlin,” Stolte said.

Nearly 19 percent of Berlin’s 3.4 million residents described themselves as Protestant, according to 2010 official data.

Some 8.1 percent said they were Muslim and 0.9 percent Jewish, while more than 60 percent said they did not adhere to any religion.

Pastor Gregor Hohberg said it had been crucial to also get the center’s Jewish and Muslim partners involved right from the start, well before work got underway on building it.

“From the beginning we wanted it to be an inter-religious project, not a place built by Christians in which Jews and Muslims would then be added,” he said.

Imam Kadir Sanci, who’s of Turkish origin, told AFP that a Catholic-Protestant church in western Germany had inspired him to dream that such a center could be possible.

“When I was doing my Muslim theology studies in Frankfurt, I had seen in the neighboring town of Darmstadt, a Catholic church and a Protestant church under the same roof,” he said. “I said to the priest it would be great to one day have a shared place with Muslims. But the priest told me ‘be patient, it took us 600-plus years’,” the imam said.

Architect Wilfried Kuehn, whose design for the new building was chosen in 2011 from around 200 entries in a competition, said it had posed many challenges that spanned architecture and theology.

“It was a challenge to try to combine the differences and the universal aspects. It was a question of not mixing the religions while ensuring mutual recognition,” he said.