Philadelphia (CNN)The note Mrs. Chambers placed on her kitchen table before she left home Saturday was short and to the point -- like a message you might leave to say you'd stepped out to buy a gallon of milk.
The Pope's people: Meeting strangers in the crowd
But Mrs. Chambers, who's 88 years old, had a much grander plan in mind. And she thought one of her nine children, 24 grandchildren or 17 great-grandchildren might worry about her whereabouts. So she left an explanation.
"I went to see the Pope," her note said. "This is my special pilgrimage."
It wasn't until she arrived in downtown Philadelphia -- some five hours and 8 miles later -- that she, and I, would discover how special it was.
Try to spot a familiar face in the crowds at the World Meeting of Families and you'll get lost in the sea of souvenir T-shirts and security barricades.
But if you really want to understand why so many people came to the City of Brotherly Love this weekend, take a moment to meet a stranger.
That's what I did when I got to the Benjamin Franklin Parkway on Saturday night. And here's who I found:
Dana Plunkett was leaning against a sign and gently braiding her 11-year-old daughter's hair when we met.
Plunkett, her husband and her daughter arrived in Philadelphia on Wednesday and spent a few days sightseeing and attending events at the World Meeting of Families. It's been fun for her and her husband, she said, but they did it for their daughter.
"Kylee has autism," Plunkett told me, "and she loves the Pope."
Learning about Francis and following the rituals of the Catholic Mass have brought her daughter comfort, she said.
"I think that's why we like the Pope so much, because he's caring for people with disabilities," she said.
And the Pope's message has helped give all of them strength.
Dealing with autism, she said, is time-consuming.
"We don't have a lot of time for each other," she said. "This meeting just kind of proves how much people need each other. You're called to love one another."
Paul McCarthy was standing beside a striped picnic blanket, popping snack food into his mouth and surveying the scene around him with a smile on his face.
Along with a church group of some 200 people, the 50-year-old stay-at-home dad came here from Ridgewood, New Jersey, with his wife and two children with a singular goal: "To have a connection, to be in his presence, to potentially see his gaze -- and have my children share that."
He doesn't even mention Francis by name. And he doesn't need to. His reverence and enthusiasm make his meaning clear.
The importance of humility, serving others and trying to protect the weak and defenseless are ideas he's long tried to instill in his children.
Often, they'll pray for families who have no home or who go to bed hungry.
"I have them pray for a cause that's connected to them and then one that's greater than them," he said.
The Pope's given new momentum, McCarthy said, to his push to help his children see the world beyond their comfort zone.
"When the Pope -- and the world -- are talking about things," he said, "it drives that home in a way that I can't."
Adriana Perez was sitting on the ground with her 11-year-old son, Oscar, leaning back against her shoulder.
Attending the World Meeting of Families all week, she said, has been humbling for them.
"I realized we went through difficulties, but not as many as other families," she said.
When Francis speaks, the 32-year-old housekeeper hangs on his every word. So many of the things he's said during this U.S. visit rang true with her.
"He said it in Washington. He is also the son of immigrants. It is like he feels what we live through in this country," she said. "I feel that he understands us."
Perez came to the United States from Quetzaltenango, Guatemala, a dozen years ago. She's struggled to learn English and find work. To pick up new vocabulary, she watched hours of Food Network shows. She's asked her son, who was born in the United States and speaks both English and Spanish fluently, for help.
She says she understands English now, but is still timid about talking. When I spoke to her in Spanish, her look of concern as I approached switched to a warm smile.
"We've faced a lot of discrimination from a lot of people," she said. "They look at us as strange, but we are people."
As for Mrs. Chambers -- well, I almost didn't meet her at all.
I was looking off in the distance, straining to catch a glimpse of the stage where the Pope would soon be preaching, when I saw a man glance down at my press pass.
"Do you want to hear a good story?" he asked me.
Really, at the moment, all I wanted was to hear what the event's emcee was saying. But thankfully, my reporter's instinct kicked in and I said yes.
James Pope (yes, that really is his name; he showed me a credit card to prove it) was really pumped to tell me what had just happened. At the entrance gate, he'd run into a woman whose newspapers he used to deliver decades ago.
The woman, he learned, had walked all the way from their hometown of Collingswood, New Jersey -- some 8 miles away. When he saw her, she didn't have a ticket to the event or know how she was going to get in. But suddenly, her fortune turned.
Another woman overheard the two of them chatting near the entrance and offered her an extra ticket.
"Meet Mrs. Chambers," said Pope (the 45-year-old steamfitter in Philadelphia, not the 78-year-old Bishop of Rome). The white-haired woman beside him was waving a Vatican flag and grinning. She patiently gave me her full name: Marcella Louise Theresa Griffin Chambers.
"This is like a miracle," she said, marveling that she'd found a friend when she arrived and managed to get inside. "I would have been lost if it weren't for him."
Her appearance was both polished and practical. She wore crisp white pants, a sparkly top, a smart blazer and tennis shoes. She knew she'd have to walk some of the way when she left home just before 2 p.m., but there were more road closures and transit shutdowns than she'd expected. She hadn't realized it would be quite so far.
Still, she said, there's no doubt the trek was worth it.
"I did it for my children," she said.
And she did it for Francis.
"He is the most people-loving pope," she said.
I asked her if she'd managed to see him when the popemobile rumbled by a few minutes earlier.
"Well, they go by so fast," she said, sounding a bit resigned.
"But I was here," she added, flashing a triumphant smile. "And I saw him."
I've spent the past five days following Pope Francis from city to city on his marathon U.S. tour. Time and again I've heard him and other speakers talk about the importance of remembering the stranger.
It's a biblical reference the Pope and other religious leaders often use to discuss immigration.
But during my weekend in Philadelphia, the phrase took on another meaning.
The families I met here faced different struggles. But they all had one clear thing in common: They came to the World Meeting of Families searching for something -- and left beaming and buoyed by their brush with the Pope.
They are strangers I'll certainly never forget.