Ultimately the proper response to the question is probably: anywhere, anytime, because it is the same Mass, the same sacrifice of the Lord on the Cross at Calvary.
But having said that, try to consider where that eternal and cosmic sacrifice might mostly clearly shine through to you. I’m not referring to churches just as architectural works, but as places where the liturgy continues to be offered and is at home there.
I could imagine answering for myself that it would be the London Oratory (often called the “Brompton Oratory”; photo above), for the solemn Mass offered every Sunday at 11 a.m. The grandeur, integrity, and solemnity in the celebration of the Mass there must come very close to parting the veil. Also, even though the church there—the Church of the Immaculate Heart of Mary—is a magnificent neo-baroque edifice, it has certainly not become a museum of past glories, like many churches in Europe (and elsewhere) have been, but is the center of a thriving parish. That must surely affect the tenor of the liturgy as well.
I may or may not ever be able to attend Mass there, however. So I would like to offer two other possibilities, in the United States, which are places where I have in fact been. I offer them with the hope that others will volunteer their own suggestions in the comments. Think of this as a kind of church swap meet, which is really the purpose of this post.
(I have heard some great homilies, and have certainly had some singular experiences at Masses I have attended around the country and elsewhere, some wonderful and some not, but I am not focusing on that here, but rather on the place itself and on the ordinary conduct of the liturgy there.)
• The Sunday morning 6:30 Tridentine Mass at the Serra Chapel at San Juan Capistrano, California.
The Serra Chapel is not exactly isolated because it has troops of tourists in and out of it most of the week and is just a stone’s throw away from the basilica of San Juan Capistrano, where hundreds and hundreds of people attend Mass, but when I was there in the Chapel, it was positively cave-like, and the accumulated smell of centuries of incense and burning candles reminded me of the old monasteries on the high plains of Tibet. More than smells—when one walks in, the accumulated devotions of centuries of use become almost palpable and nearly overwhelming. And right outside the door is a splendid courtyard garden. It is a jewel.
• The Sunday afternoon 5:30 Tridentine Mass at Stella Maris Catholic Church at Sullivan’s Island, South Carolina.
Stella Maris was built after the Civil War with bricks from the ruins of Fort Moultrie next to it. The bell tower looks out across the bay to Charleston in the distance. After Mass, I remember clumps of smiling altar boys in starched cassocks standing under palmettos and blooming crepe myrtle to shield their eyes from the sun. The wide white beach is just across the park lawn. The dark and sometimes creaking wood inside is under a wooden dome rather like an overturned ship. The Mass attendance is large enough that people stand along the outer aisles, as I remember Masses from my young days. No tank tops or flip-flops. It is a very “Say the Black Do the Red” kind of place, and the parishioners are attentive and reverent during Mass and cordial and funny afterwards. As with the Serra Chapel, the weight of history over it feels profound, but sits lightly upon it.
Now that I’ve listed them, I notice that both of these are Tridentine Masses in small, out of the way places. Perhaps I therefore imagine Catholic worship in the future will be driven into the catacombs, as it were, or light out for the territories, and that, in the end, these sorts of places may be where one finds the remnant at prayer.
Just so that you know that in principal I am entirely open to suggestions of more unusual places, I offer as an example, the notion that the most extraordinary Novus Ordo Mass I could imagine (assuming it was offered ad populum) might take place on a poured concrete table in the abandoned cooling tower #3 of the Satsop nuclear power plant in Washington State. It may be that the celebrant would not even have to wear a mic. No puppets, though, please, or streamers, or liturgical dancers, just the tremendous whoosh of upward movement to heaven. A sort of close encounter of the liturgical kind.