Pope Francis acknowledges the crowd of faithful as he arrives in St. Peter's Square for his Inauguration Mass on March 19, 2013 in Vatican City, Vatican. The inauguration of Pope Francis is being held in front of an expected crowd of up to one million pilgrims and faithful who have crowded into St Peter's Square and the surrounding streets to see the former Cardinal of Buenos Aires officially take up his position. Pope Francis' inauguration takes place in front his cardinals, spiritual leaders as well as heads of states from around the world and he will now lead an estimated 1.3 billion Catholics.