A Presbyterian congregation in Dungiven, County Londonderry, is claiming a first for the UK.
They believe they have the only bomb-proof Sunday School in the country, after taking over a former police station.
The Church bought the three-storey fortified structure, complete with cell, for £175,000 last year.
The congregation planned to use it as a car park, but then decided to keep the police station for Church activities.
The children are now taught in a room which was once used for interrogation.
"This was a real fortress, up in the roof there is six inches of reinforced concrete to protect against mortar attacks," explained church committee member Ian Buchanan.
"The walls are three foot thick with reinforced concrete, everything is reinforced to the highest degree to make it totally bomb-proof."
He added: "I think I can safely say we have the only bomb-proof Sunday School in the whole of the UK."
The Church has spent more than £200,000 transforming the building and much of the work was carried out by members of the congregation.
It includes a new kitchen, elevator, crèche facilities, gym space and meeting rooms.
With a congregation of about 90 families, the Church has been involved in a massive fundraising campaign to pay for the work.
Church member Gladys Carmichael said it was a real team effort.
"When I saw the condition of the building at first, I thought it could never be used for Church activities but the transformation is remarkable and it now feels so homely," she said.
"There are lots of rooms now for the Sunday School children and the older groups to meet and play games and if any of the kids misbehave we can also put them in the cell to cool off."
The former Dungiven PSNI station is one of 80 police bases which have been sold off over the past 10 years, raising about £26m for the public purse.
Most have been demolished and the sites used for other purposes such as housing.
But that was never an option for the congregation in Dungiven.
"When we discovered what it was going to cost to demolish the building it was an easy decision to retain it" explained the church's Minister, the Rev Clive Glass.
"When we discovered what it was going to cost to demolish the building it was an easy decision to retain it" said the church's minister, the Rev Clive Glass.
"We also decided to keep many of the trappings inside.
"It is good to have some of the original aspects of the building there too, just to remind the children and young people who maybe have never been to the station before in their lives, just what this was originally," he added.
The new church building has been called "the Station" and will be opened officially later this month.