It is expected that the Mass itself will gather about one million people in the square and along the Via della Conciliazione, which leads up to St. Peter's Basilica. Moreover, lots of people will gather in public squares around the city, where the Mass will be projected on big screens.

John XXIII
John XXIII was beatified on 3 September 2000 by Pope John Paul II. The case of John XXIII canonization is a bit special, as Pope Francis waived the requirement for a second miracle. Vatican rules require one miracle for beatification and one for canonization, but the pope may elect to set the rule aside.

John Paul II
During the funeral of Pope John Paul's, the crowds shouted Santo subito or Sainthood now!. Also in this case special conditions were applied - Pope Benedict XVI waived the traditional 5-year waiting period for the canonization process to begin. John Paul II's beatification took place on Divine Mercy Sunday too and was the fastest in history: just six years after his death. His second miracle for canonization concerned a Costa Rican woman who was cured of a cerebral aneurysm.