PHILADELPHIA (CBS) — During the papal parade in Philadelphia on Sunday, Pope Francis visited the “Knotted Grotto,” located outside the Cathedral Basilica of Saints Peter and Paul.

The “Knotted Grotto”is a public art installation that became a brief sanctuary for reflections by the faithful.

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As KYW’s Steve Tawa reports, artists constructed the 20-by-13 foot domed structure made of ash and mahogany, a representation of one of Pope Francis’ favorite paintings entitled “Mary, Undoer of Knots.”  It depicts Mary, surrounded by angels, untying knots to form a long strip.

Sister Mary Scullion, co-founder of the homeless advocacy group, Project HOME, says Philadelphians jotted down their thoughts on ribbons of fabric.

“It’s just a profound sense of joy and gratitude to know that Pope Francis took the time to come to the Grotto and to bless all these knots and struggles and prayers of so many people from all walks of life. We’re just so grateful to him and to the Archbishop who made intersession on our behalf to get him to come here. We’re just so grateful, just so grateful,” said Sister Scullion during an interview with CBS 3 Eyewitness News.

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During the Pope’s visit to the Knotted Grotto, he also hugged Sister Scullion.

“We’ve been in tears throughout the many weeks just listening to people’s stories, their struggles, their knots, and their faith, you know hoping and praying for an answer to their prayers and to their struggles. God hears all our prayers and struggles, but to have them blessed by Pope Francis I think will give a lot of consolation to people who are really suffering and in pain,” she said.

WATCH: CBS’3 Pat Ciarrocchi reports on the Knotted Grotto

“Before we put up the grotto, we went into prisons and soup kitchens and shelters so people that normally may not be able to participate did participate in that.”

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The Knotted Grotto is located outside the Cathedral Basilica of Saints Peter and Paul from now through the end of the Papal Visit weekend.