I have to admit that I haven’t been to every church in Madrid — that would be a monumental project — but I would still place my money on the very best church being Iglesia de San Antonio de los Alemanes (literally, Church of St. Anthony of the Germans).
What makes this Baroque church so amazing are the floor-to-ceiling frescos, painted in the mid-1600s by the Italian and Spanish duo of Luca Giordano and Francisco Ricci. The central ceiling panel depicts St. Anthony receiving baby Jesus into his arms.
To be clear, this is St. Anthony of Padua, the patron saint of the poor (and of sailors, fishermen, and travelers, among other things). The church is known the “Church of St. Anthony of the Germans” because Queen Mariana of Austria designated it a refuge for German immigrants in 1668. It’s worth noting that the church had been originally founded in the early 1600s as a spot for Portuguese pilgrims — but Queen Mariana was not a fan of recently-independent Portugal, so she gave the church to the Germans instead.
If you look beyond the central panel, the ceiling is a wonder of Baroque trompe l’oeil. You really feel like you’re in a building that stretches up to the heavens.
The base of the ceiling is ringed by eight saints, of which a somewhat jaunty-looking Saint Sabina is my favorite.
The walls of the church are decorated with large panels celebrating St. Anthony’s many miracles. These include St. Anthony preaching to the fish (they listened!) …
… St. Anthony preaching in a thunderstorm (everyone stayed dry!) …
… and the miracles of the mule (it bowed down to the saint!) and the miracle of the severed foot (he reattached it!). That last story is a little gruesome — the young man in question chopped off his own foot with a hatchet because he felt bad about having kicked his mother — but all’s well that ends well.
The mid-1700s altar (the original burned down) features a statue of St. Anthony holding the baby Jesus …
… but it’s sort of dwarfed by everything else around it.
A small early-20th-century organ sits over the church entrance, and just below it hangs a relatively tiny medallion of Queen Mariana herself:
A visit to the church is absolutely worth the several Euro entrance fee. To help you understand what’s going on, they’ll give you a loaner document (available in several languages), though there’s so much artwork that it still took me a while to make sense of it all. But you can absolutely enjoy this place with delving into the iconography; it’s lovely just to sit in wonder at the beauty of it all.