Established by President John F. Kennedy on March 1, 1961, barely a month after he took office, the Peace Corps has always seemed such a quintessentially '60s initiative.

The volunteer program, which has sent more than 200,000 American volunteers to 139 countries over the last half-century, is as robust as ever, said organizers of Sunday's Peace Corps Around the World Expo at the National Constitution Center.

"Actually, the number of volunteer applications has been going up," said Anne Baker, vice president of the National Peace Corps Association, which cosponsored the event. President Obama "has been talking a lot about volunteerism and national service, and people are responding."

Baker, who served in Fiji from 1985 to 1987, was one of more than 20 Peace Corps veterans who offered accounts of their experiences in an afternoon of speeches, workshops, and panel discussions.

Former volunteers staffed exhibit tables from more than a dozen host countries, including Ukraine, Kenya, and Jamaica.

"I'm here to share what a phenomenal, life-changing experience I had," said Center City's Ari Weiner, 30, who lived from 2005 to 2007 in the Moldovan city of Balti, where he helped businesses secure micro-loans.

Weiner was attracted to the Peace Corps because, he said, it provides the world with "cultural ambassadors from America who want to help . . . people abroad," and with no selfish motives.

Marlton's Alicia DeMarco, 39, used her expertise as a high school teacher to work as an English instructor in Derecske, a Hungarian village near the Romanian border.

There was some serious culture shock, she said, when she arrived.

"One day I was out jogging, and the villagers didn't know what to make of it. Old ladies put down their shopping bags and watched me run past," she said. "I got two questions: 'What are you running away from?' and 'Where's your husband?' "

For some, the culture shock is worse once they return to America, said DeMarco, who helps run the Philadelphia chapter of the National Peace Corps Association, which helps volunteers readjust.

Albert Wellstein, 55, an agricultural adviser in Highgate, Jamaica, from 1981 to 1983, said he still missed the "Edenic" gardens and farms where he worked. Returning to Center City was a bit of a rude awakening, he said.

Potential Peace Corps recruit Jessica Granacher, 20, checked out the Ukraine table, staffed by Nancy Iott, 68, a retired teacher and restaurateur from Narberth.

Granacher, a Drexel University sophomore, said she was drawn to the Peace Corps because it offered joint programs with many graduate schools. "I'm looking to Europe and Africa, where I'd want to do environmental work," she said.

Sarah Heidke, 29, a paralegal from Fairmount, said she was almost ready to mail in her Peace Corps application.

"I want to experience how different cultures work and how different people see the world," said Heidke, who studied social work at Messiah College in Grantham, southwest of Harrisburg.

"I've always been a service-oriented person. I was raised with the idea that giving back is the most important thing."