The pope opened the Jubilee by opening the holy door of St. Peter's Basilica shortly before the Midnight Mass on December 24, 1999. Most of the time, the holy doors of the patriarchal Basilicas are cemented shut. On the occasion of a Jubilee year, the pope opens the doors as a symbol of opening the doors of grace. Pilgrims visiting the basilicas to gain the Jubilee indulgence enter the basilicas through these special doors. Throughout most of the Jubilee year, long lines were queued up to enter the door.