To the north of the Piazza stand the Porta del Popolo and the ancient church of Santa Maria del Popolo. The Porta del Popolo was reconstructed to the current appearance by Pope Alexander VII in 1655, to welcome Queen Christina of Sweden to Rome after her conversion to Roman Catholicism and abdication. It was designed by Bernini: whereas such festive structures elsewhere were built of weather-resistant plaster, in Rome the structure was more permanently executed in stone. Opposite Santa Maria del Popolo stands a Carabinieri station, with a dome reflecting that of the church.