The French revolution took place at the end of the 18th century and I'm sure that a lot of churches in Paris (or any French city) were demolished in a big FU to God. I can't recall something similar having taken place in Portugal at the time. Or anywhere else.
Official anti-clericalism and state atheism lasted for a very short period of time, not nearly enough to do any damage to the churches save for surface vandalism and pillaging of the statuary, furniture etc.
The great victims of the Revolution are the monasteries and the castles. The monasteries were officially dissolved (in a movement similar to what had happened in England under Henry VIII), their land redistributed and their buildings sold for stone. The same happened to aristocratic holdings and most Medieval castles that somehow managed to survive until then were destroyed over the first half of the 19th c.
That's how we've lost some of the most iconic monuments of Western civilization (I'm in particular thinking of Cluny, whose archives were burnt, manuscripts vandalized and stolen, stones parted out).
This happened everywhere that the Soviet Union "spread" to. Churches were demolished, desecrated, or burned. Some were re-purposed, but many were destroyed.
Well.. start by reading the aftermath of the Lisbon earthquake.
The persecution took place through about a century to carefully avoid drastic events as you'd later see in France, thus reducing public opposition/outcry. Contrary to France, there was no need for "revolution" because liberals were already in power since the earthquake. More details here: https://pt.wikipedia.org/wiki/Extin%C3%A7%C3%A3o_das_ordens_... (need to translate)
My home town is Coimbra. The whole Rua da Sofia (Street of Knowledge) was expropriated and left to abandonment or sold for whatever other purposes without shame on the 18th century. Worse destiny had the church of São Cristovão, presumably built by the father of the first portuguese king: https://www.cm-coimbra.pt/wp-content/uploads/2012/03/coimbra...
For a political movement aimed to bring light into the masses, liberals sure dived the empire into some really dark decades that we'd never recover from afterwards.
