Karlskirche (St. Charles' Church, completed in 1737) is a baroque church located on the south side of Karlsplatz in Vienna, dedicated to Saint Charles Borromeo.
It's considered the most outstanding baroque church in Vienna, as well as one of the city's greatest buildings.

St Charles' Church was created by Johann Bernhard Fischer von Erlach. The design was influenced by the Hagia Sophia in Istanbul and Trajan's Column in Rome.