The Cathedral Basilica of Saints Peter and Paul, the head church of the Roman Catholic Archdiocese of Philadelphia, is located at 18th Street & the Benjamin Franklin Parkway on the east side of Logan Square in Philadelphia, Pennsylvania. It is the largest Catholic church in Pennsylvania and is listed on the U.S. National Register of Historic Places as the Cathedral of Saints Peter and Paul. In 1979, the Cathedral was visited by Pope John Paul II, where he went on to celebrate Mass. It was erected in 1864. Photo by Carol Highsmith.