Villa 21-24 is a slum so dangerous that most outsiders don't dare enter, but residents say Jorge Mario Bergoglio often showed up unannounced to share laughs and sips of mate, the traditional Argentine herbal tea shared by groups using a common straw.
People here recall how the Buenos Aires archbishop ditched a limousine and would arrive on a bus to their little chapel; how he sponsored marathons and carpentry classes, consoled single mothers and washed the feet of recovering drug addicts; how he became one of them.
"Four years ago, I was at my worst and I needed help. When the Mass started he knelt down and washed my feet. It hit me hard. It was such a beautiful experience," said Cristian Marcelo Reynoso, 27, a garbage collector trying to kick a cocaine addiction through the church's rehab program.
"When I saw the news on the TV, I began screaming with joy, and look, I'm still trembling," Reynoso said. "El Chabon (The Dude) is so humble. He's a fan of San Lorenzo (the soccer club), like me. You talk to him like a friend."
Long after he became a cardinal in 2001, this "prince of the church" wore a simple black T-shirt with a white collar. For many at the slum's Caacupe Virgin of the Miracles Church, it's nothing short of a miracle that their friend is the pope.
"He was always part of our slum," housewife Lidia Valdivieso, 41, said after praying while resting her palm on a statue of St. Expeditus, patron saint of urgent and impossible causes. Her 23-year-old son has cerebral palsy and is learning carpentry at the church's technical school.
"When I heard the news I couldn't believe it. Having a 'papa villero' (slum pope) is the most beautiful thing that can happen to us. I still remember him going on long walks through our muddy streets or talking to our children," Valdivieso said.
Inside the concrete block chapel, there's a painted message commemorating Bergoglio's inauguration, and another big painting of Pope John Paul II, but no sign of Benedict XVI whatsoever. Near the altar, there's a large black-and-white poster of Carlos Mugica, an iconic Argentine slum priest who was killed in 1974 by a right-wing death squad intent on eliminating the "liberation theology" he preached.
Bergoglio never favored liberation theology because of its alliances with armed leftist guerrilla movements in the 1970s. But he has done much to follow in Mugica's footsteps, sponsoring all sorts of outreach programs in Argentina's slums.
This can be messy work, obliging priests to challenge drug dealers for the slum-dwellers' allegiances, and putting their beliefs, even their lives, at risk. Sometimes compromises must be made.
Just a few steps from the chapel, melted candles stand in a red shrine to the pagan folk hero Antonio "Gauchito" Gil, a 19th century outlaw revered among Argentina's poor for sharing his stolen bounty with the poor.
Many Argentines are as likely to pray for miracles from "Gauchito" as they are from authorized Catholic saints, but Bergoglio didn't object to the shrine's presence next to his chapel.
"For more than 20 years he came here. He's always been close to us and his impact on this slum is huge," said the parish priest, Lorenzo "Toto" de Vedia.
Cameras followed Bergoglio once as he washed the feet of 12 young men at a rehab center. "Then he kept coming back, taking confession and counseling them," Vedia said. On the priest's desk lay a newspaper with a huge, one-word headline: "FRANCISCO."
"You can tell that the church is going to change," Vedia said. "The fact that he chose the name Francisco says it all. It says: 'Let's stop messing around and devote ourselves to the poor.' That was St. Francis* message and now 'Francisco' can live it."
In his first appearance at St. Peter's Square, the first Latin American pope bowed to the crowds and asked for their blessing. Back in Argentina, his friends in the slums recognized the gesture as the same sort of humility that won their hearts.
In the 13th century, St. Francis of Assisi made it his mission to respond to the poor and show that through simplicity and love, a stronger foundation for the church could be built.
Pope Francis' "mission is now to go on a pilgrimage to all lands, to walk with the people, to lead a church that walks," said Mercedes Trovato, 24, a youth volunteer who wore a wooden cross around her neck.
The pope's sister, Maria Elena Bergoglio, said she is very confident that the pomp and protocol of the Vatican won't dent his lifelong humility. His message to Argentines to spend their money on charities instead of for trips to Rome to see his installation in the Vatican on Tuesday is a strong sign that he won't change, she said.
"That message ... makes me feel like he is still on the same path, that he hasn't been affected for the moment, at least," she said in an interview with The Associated Press at her home 25 miles west of downtown Buenos Aires. "There is no worse poison than power."
She added that her brother's preference "is for the poor, the weakest, the old, children."
"He has a clear preference for the poor," she said.
Nor did he ever express a desire to become pope, she said. "We would challenge him about it and he would say, 'Oh, please!'"
Bergoglio's friends say he's fundamentally shy. He hardly ever grants media interviews, preferring to speak from the pulpit. But he did agree to chat recently with Jaidr Flores, a 22-year-old host on the parish's Radio FM La 96.
"He was hesitant at first. But I convinced him, and at the end of the interview, he started laughing and said: "You did it! You got me on air!'" said Flores. "One day I went to visit him at his office and I was amazed to see how many pictures of the volunteers and recovered drug addicts from this community he had on his desk. He truly cares for us."
Luis Andres Henao on Twitter: https://twitter.com/LuisAndresHenao