By Robin Culverwell

PHILADELPHIA (CBS) – An unusual, interactive art exhibit is coming to the grounds of The Cathedral of Saints Peter and Paul just in time for Pope Francis’ visit at the end of September.

The exhibit is based on the Baroque painting “Mary Untier of Knots” — which shows the Virgin Mary undoing a knotted ribbon.

Knots have long symbolized struggle, so the idea here is to write your struggle on a ribbon and tie it in a grotto artist Meg Saligman will build. In doing so , she says, you are giving your troubles to God:

“If you have a little in you that day you can also take someone else’s struggle and untie their knot and say a prayer for them.”

If your ribbon stays in the grotto, Pope Francis will pray over it, as will others who stop by.

If you can’t get there to leave a prayer, starting in mid-June, you can write your struggle at and a scribe will post it in the grotto for you.

Saligman says Sister Mary Scullion approached her about this project to give voice to the homeless and underserved in society.

The exhibit will be installed in late August, about 30 days before the Pope’s visit.

Listen to the full podcast (runs 9:14)…