The Knotted Grotto sits at the steps of the Cathedral Basilica of St. Peter and St. Paul in Philly, where the Pope will celebrate mass Saturday morning.
It's the brainchild of Philly artist Meg Saligman -- all are welcome.
"We love the fact that it's all inclusive, and right at the foot of the Basilica," said Saligman.
The idea is to write your prayers, concerns, hopes, fears, and then tie it to the Grotto.
"Some are dark worries," said Seligman, "Some are sadnesses that are unspeakable, and we say to people -- when you put them down they're anonymous but they’re not private because they are in a public installation, and someone else will come along and untie yours and say a prayer for it."
The artist says her team prepared 100,000 ribbons and they're running out.
Robert Micaletti says that for him, the miracles are already flowing.
"I said a prayer to St. Francis," said Micaletti, visiting from Florida, "to help me to get a ticket to see the Pope and my prayer was answered."
Visitors are hoping that Pope Francis will notice the work and bless it.
Saligman says that it's hard to miss, now that it's grown so much.