The Prince of Wales and his wife Camilla, Duchess of Cornwall, greeted long lines of gushing fans, impressing many with their down-to-earth charm.
"She actually offered her hand to me," said Debbie Lefevre, 49. "I was shocked."
The royal couple is on a two-day trip to the U.S. that focuses on youth development, urban renewal and environmental stewardship.
Sharon Thaler, 52, of Philadelphia, waited hours to get a glimpse of royalty. She said the prince was quite surprised at how long she had been waiting in the cold.
"In that case, I hope you have a stiff case waiting at the end of the day," he told her.
Prince Charles and Camilla were to meet the mayor, governor and other officials in the first of about a half-dozen public appearances.
After Independence Hall, the couple will meet with students at the Liberty Bell and receive a replica of the national icon. They will then attend a reception with community leaders at the National Constitution Center.
Next on the itinerary are stops in West Philadelphia, where the heir to the British throne will focus on youth development and urban revitalization. West Philly is home to some of the city's poorer and more violent neighborhoods.
The couple will visit a mural titled "Reading: A Journey," one of 2,700 created by the city's Mural Arts Program. They will then meet community members and mural artists at a reception at a nearby church.
James Helman, an activist in the city's Grays Ferry section, said he looks forward to speaking with Prince Charles about the mural called "Peace Wall" that was created in his neighborhood.
"I think the prince is very much interested in restoring blighted neighborhoods in his own country," said Helman, 61. "Mural arts is one of the options."
The couple then plan to stop at International House, a nonprofit organization housing nearly 400 students, scholars and interns from more than 65 nations. The duchess is to meet students while the prince attends a round-table discussion of urban renewal efforts in foreign countries.
A visit to the Academy of Music's 150th anniversary concert is scheduled for Saturday night.
On Sunday, the prince and duchess plan to attend services at Arch Street Presbyterian Church, spiritual home of the Welsh community in Philadelphia.
The couple are then scheduled to take a private train about 90 miles to New York, where they plan to visit a social services agency in Harlem and Prince Charles is to receive an award from Harvard Medical School's Center for Health and the Global Environment.
Prince Charles has already been attacked in Britain for endangering the environment by flying to the United States to accept the award in person, rather than by video linkup, reports CBS News correspondent Michelle Miller.
Prince Charles has long been involved in environmental causes. "You know if you look at the latest figures on climate change and global — I mean, they're terrifying, terrifying," he said on CBS' 60 Minutes.
"He's been banging the environmental drum now for 30 years and I'm sure he'll die doing the same," Prince Charles's biographer, Howard Hodgson told CBS. "By the '80s he'd become the 'loony prince.' Everyone laughed at him for being concerned about the environment — and we probably don't laugh at him anymore."
The prince and duchess last came to the United States in November 2005, when they visited the site of the Sept. 11 attacks in New York and saw the devastation caused by Hurricane Katrina in New Orleans. The trip also included stops in Washington and San Francisco.