Poland has a liberal sprinkling of utterly bonkers churches, but this is one of the best/worst that I’ve found so far. Designed in 1958 by a couple of jokers called Jerzy Kuźmienko and Andrzej Fajans, it wasn’t actually built until the 70s.
It seems to have been built by people with a fairly rudimentary knowledge of construction techniques and health and safety requirements. The surface of the concrete roof is as rough as it looks, with the reinforcing metalwork poking through in many places.
It certainly is striking though (and huge. I hope that comes across in the pictures).