A small, modest 17th-century church in Malasaña that conceals one of the most extraordinary baroque interiors in Spain. The exterior gives nothing away — a plain brick facade on a narrow street — but step inside and the entire interior is covered in vertiginous trompe-l'oeil frescoes by Italian master Luca Giordano and Spanish painter Francisco Rizi.
The painted architecture climbs up the walls and seems to dissolve the dome above. The effect is overwhelming and disorienting in equal measure. The church belongs to the Hermandad del Refugio, a Catholic charity that runs a soup kitchen and still uses the building. Visits are by paid entry (€2), usually with one of the volunteers who explains the frescoes. Closed during services and some afternoons; check the schedule before crossing town for it.