Every once in a while, we meet someone who really has made a difference. Sister Mary Scullion, of the Sisters of Mercy, has been called Philadelphia's Mother Theresa. In the course of reporting tonight's profile of her, she tried to introduce us to, and have us interview, everyone but herself about the homeless problem.

She began her efforts about 20 years ago, when homelessness became a problem that really riveted the nation's attention. She started an organization called Project H.O.M.E. Just doing that was a huge problem because she wanted to open a shelter in an abandoned casket factory close to Center City. No one wanted any homeless people anywhere downtown, and certainly not a shelter where homeless people would live.

But sister Mary wouldn't take no for an answer. The shelter opened, as did several other buildings offering shelter and services close to the heart of the city.

Today, Project H.O.M.E. is an $11-million-a-year non-profit. It has built 60 units of rental housing and renovated 19 abandoned homes, with nine more under construction. It also has helped build the Honickman Learning Center and Comcast Technology Labs, a state-of-the-art digital learning center that's the envy of even the best private schools. The goal is to build up to 100 homes during the next few years.

Clearly, Sister Mary did not do all of that by herself. But what started as something very small has turned into a program that cities across the nation want to emulate.

Sister Mary is persistent, passionate and firmly in control of what she's doing. The key, she says, is connecting with people on the street at a down-to-earth, real, unpretentious level. There's nothing phony about her. She says meeting and getting to know homeless people has made her a better person. She admires their courage and their dignity under such dire conditions. She says most people dismiss the homeless as invisible or unworthy, with no one but themselves to blame for their plight. Obviously, she doesn't see or relate to them in that way.

While we were following her around with a TV camera, she insisted on speaking to the people we encountered first, and making sure they did not mind being photographed. Her honor, her word, her credibility were at stake. One of the biggest problems she encounters in trying to get people to trust her, or anyone, for that matter.

She's a very humble, understated woman, who truly has inspired quite a difference here, and created an organization that seems well on its way to its goal -- ending homelessness on the streets of Philadelphia.