In pictures: Pope beatifies South Korea Catholic martyrs
Pope Francis was greeted by hundreds of thousands of Catholics in South Korea, as he delivered a large open-air Mass during which he beatified 124 of the country's first Catholics.
Many of the attendees were invited through their local churches from across the country. Local media reports said the crowd topped one million.
Throngs of people turned up to welcome the pope's motorcade as it made its way towards the site of Mass in Gwanghwamun square.
Gwanghwamun Plaza - the city's main thoroughfare - led to the site where many Catholic martyrs were publicly executed in the 18th and 19th Centuries.
The pope said the lessons to be learned from the martyrs were as important as ever in societies "where, alongside immense wealth, dire poverty is silently growing".
Dozens of goblets were laid out in preparation for the beatification ceremony.
Cheers from the crowd erupted when Pope Francis declared the 124 Catholic martyrs "blessed" - the first step toward possible sainthood.
A massive security operation was in force, with bridges, roads and underground stations closed and police snipers deployed to the roofs of nearby buildings.