Description:Tourists and pilgrims visit St. Peter's Basilica in the Vatican, just days after Pope Benedict XVI's stunning announcement that he is resigning from this position. Here at St. Peter's Square the pope is expected to deliver his final public mass during the traditional Ash Wednesday service. Who will be leading such events after Benedict is now the source of much speculation. Half of the cardinals who could be selected to become the new pope are from Europe.(1:06)