Karlskirche exists because of a promise: when plague swept Vienna in 1713, Emperor Charles VI vowed a church to St. Charles Borromeo, the 16th-century plague saint and his name patron, once the epidemic passed. Johann Bernhard Fischer von Erlach won the competition with the strangest and most brilliant facade in Austrian baroque — a Greek temple portico flanked by two 33-metre relief columns modelled on Trajan's Column in Rome, spiralling with scenes from Borromeo's life, all beneath a 72-metre copper-green elliptical dome. His son Joseph Emanuel finished the building in 1737.
Inside, the payoff is vertical: Johann Michael Rottmayr's dome fresco of the saint's apotheosis covers the ellipse in clouds, saints and tumbling angels. A panorama lift rises through the open interior to a platform up in the dome — close enough to see the brushwork of a fresco painted to be read from 70 metres below, with a final stair to windows over Karlsplatz. Entry including the lift runs about €9.50; the church doubles most evenings as a candle-lit venue for Vivaldi's Four Seasons played on period instruments, a fixture of the Vienna concert circuit.
The setting seals it: Karlskirche fronts a long reflecting pool on Karlsplatz — Henry Moore's sculpture Hill Arches sits in the water — making it the city's most photographed baroque exterior at dusk. It stands ten minutes on foot from the State Opera and five from the Naschmarkt and the Secession, with Otto Wagner's green-and-gold Karlsplatz Stadtbahn pavilions across the square; in December a Christmas market fills the forecourt.
