5 - Cathedral Basilica of Sts. Peter and Paul (Philadelphia, Pennsylvania)
The largest church in, and the seat of, the Archdiocese of Philadelphia. The Cathedral Basilica of Sts. Peter and Paul has hosted two papal Masses, the first of which was celebrated by Pope St. John Paul II in 1979, and the second by Pope Francis in 2015. In order to ensure that its construction would not be too expensive, the building was erected over the course of 18 years.
+© Beyond My Ken - CC4