Link to Cecil’s column: Is there a door in St Peter’s basilica that’s opened once every 100 years?
Cecil mentions “an odd tradition at St. Peter’s involving the Porta Santa, or Holy Door”. It’s worth noting that this “odd” tradition is not confined to Saint Peter’s Basilica. The three other papal basilicas in Rome (St John Lateran, St Paul Outside the Walls and Saint Mary Major) also have holy doors. The Jubilee pilgrimage and indulgence, to which Cecil refers later in the column, has traditionally required visiting all four basilicas and entering through their holy doors.