Since my wife and I travel to Italy and Mexico most years, we see lots of churches. Both societies are long associated with Roman Catholicism and the Catholics build spectacular cathedrals. I would say that, between the two countries, the homeland for the church, Italy, has the biggest and the best. After all, nothing can really compare to the Vatican and St Peters.
However, here is a very quaint and pretty church near Oaxaca, Mexico. The lush flowers around it, in the middle of January, are quite the selling point to a guy from northwest Washington. I think this is a very pretty smaller church. It is small, at least, compared to some of the churches in Italy and Mexico.