He and Cichońska spent a year and a half collecting data on these structures, many of which are unknown outside of their parish. This is the first time they have been treated as an architectural phenomenon. Despite or perhaps because of their quasi-clandestine nature, these buildings are “the most distinctive Polish contribution to the architectural heritage of the 20th Century,” says Snopek. “Through our project, we were trying to inflict a notion of pride, as many of these churches are the best pieces of architecture in their area.”

Most of them are in marked contrast to their concrete, Modernist, prefabricated neighbours: the vast housing estates that they served. Architect Wojciech Jarząbek – one of Poland’s leading representatives of postmodernism – compares the two experiences. “We had already had several years full of passionate work on a housing project for 23,000 inhabitants,” he says, “but this ended with strong frustration after seeing the very bad quality of execution, and not seeing on site any of the architectural details we had designed.” He wanted his Church of Our Lady, Queen of Peace in Wroclaw “to stand in contrast… to the surrounding architecture”.