The area around Gwanghwamun Plaza was packed with people on Saturday as Pope Francis beatified 124 Korean martyrs.
Press reports here claimed some 1 million people gathered to watch, and Vatican spokesman Father Federico Lombardi said police told him it was 800,000.
But the Seoul Metropolitan Police, which was in charge of security on the day, estimated the figure at about 175,000.
If the area between Gwanghwamun Plaza and Seoul Plaza in front of City Hall is fully packed with people, it would not hold more than 500,000, a police spokesman said, but participants of the mass sat on the ground, reducing the density.
Meanwhile, the pope had a hectic weekend. On Saturday morning, he left the Embassy of the Holy See to visit a cemetery in downtown Seoul where Korean martyrs are buried. Then, he paraded through Gwanghwamun in his car ahead of the mass.
In the afternoon, he flew by helicopter to a Catholic charity village for the homeless and sick in Eumseong, North Chungcheong Province.
On Sunday, he made a return trip to Seosan, South Chungcheong Province to lead a mass on the final day of World Asian Youth Day. He traveled a total of 490 km over the weekend.