They have been repurposed for everything from strip joints to nightclubs and pizzerias, but now the Vatican is urging Catholic countries not to allow deconsecrated churches to be used for profane purposes, in the first conference dedicated to the issue.
Falling congregations, a lack of clergy and crippling maintenance costs have meant that thousands of Catholic churches around the world are being decommissioned and turned into restaurants, pubs, cafes and even skateboarding venues.
More than 500 Catholic churches have closed in Germany since 2000, while in Canada one fifth of churches were deconsecrated in the same period.
In Holland, an estimated 500 churches are due to fall out of religious use in the next decade, and there is a danger they will end up being used for "inappropriate activities", as one delegate put it at the 'Doesn't God Live Here Any more?' conference in Rome.
Paul-Andre Durocher, the Archbishop of Gatineau in Canada, said: "I know of a little church in northern Ontario that was turned into a strip club. It went up in flames, thank God. That's one of the worst examples."
In Prague, a church was turned into an ice cream parlour, while in Arnhem in Holland, a former church -became a skateboarding hall.
In Asti in northern Italy, a church has been turned into a bar called 'Il-Diavolo Rosso' - The Red Devil.
Earlier this month, a scandal erupted in Naples when a former church was used for a Hallowe'en party, with young women dressed in sexy witch outfits and leather mini-skirts sitting on the altar.
In 2005, a late 18th-century Catholic church in Liverpool was sold and converted into a nightclub, which was "still very much regretted by the Catholic community", according to the Catholic Bishops' Conference in the UK.
Pope Francis acknowledged a decline in the number of faithful and a dearth of priests, but said that deconsecrated churches could be given "a new life", preferably in service of the poor.