King Felipe VIand Queen Letizia joined the throngs of devotees wavingSpanishandVaticanflags in Cibeles Square.
The mass comes on day two ofPope Leo'sseven-day visit to Spain, a traditionallyCatholicbastion where religious observance has been declining sharply in recent years as it is in much of Western Europe.
A huge logistical and security operation was in place for the event, after which the pope led a traditional procession along a route lined with white and yellow carnations theVaticanflag colours.
Organisers said there were more than 1.2 million people attending in the square and the surrounding area.
The mass comes on day two of Pope Leo's seven-day visit to Spain.
Nico Aldeanueva, 28, who was visiting from Philadelphia in the United States, said the pope was "a very unifying force in a moment where we have division across so many different fronts".
"We have, it seems like, never-ending conflict, and for the time being here you get to hit pause and get to enjoy the moment and feel the faith."
Ana Milagros, 64, who was waving a Vatican flag, said she thought theUS-born popeseemed "approachable" and "very sincere".
"There is a lot of polarisation and differences in politics, in social matters, in the economy," she said, adding: "The pope is trying with this visit ... to help all of us."
Focus on migration
Later on Sunday, Pope Leo will meet leading lights of culture, sport and the economy at an arena with the aim of fostering dialogue between faith and modern civil society.
Around 56 percent of Spaniards identify as Catholic compared to 90 percent in the 1970s, according to a survey last month by the Centre for Sociological Research, an autonomous government body.
On Saturday, 500,000 mostly young attendees congregated with Leo outsideReal Madrid's Bernabeu stadium for a prayer vigil that stretched into the night.
Leo kicked off his visit with pomp and ceremony at a reception at Madrid's royal palace, where he called for an end to "polarising narratives" and "sterile simplifications".
The pope also praised Spain, whose left-wing government has sparred with his native United States as well as Israel over wars in theMiddle East, for its "active commitment to peace and solidarity among peoples".
Leo is due to visit Barcelona on Tuesday and Wednesday, where he will notably bless the Sagrada Familia basilica's recently completed tower, which made it the world's tallest church.
His trip will end with afocus on migration on Thursday and Friday in the Canary Islands, a key destination for irregular arrivals. Thousands have died in the Atlantic Ocean trying to reach them.
(FRANCE 24 with AFP)
Originally published on France24
