CHICAGO -- A marking on a freeway underpass is creating a stir in Chicago.

Obdulia Delgado said she was driving home along Fullerton Avenue on April 10 after getting off work at St. Elizabeth Hospital when she saw the Virgin Mary on the wall of the Kennedy Expressway underpass. She quickly pulled over and examined the form, and then began praying.

"Monday through Friday I go to school, and Saturday and Sunday I work, so since I haven't been able to go to church, I asked her, 'Please help me with school because I'm having my finals,' but I felt like she was like, 'If you can't come to me, I'm going to go to you,'" Delgado said.

Delgado said she rushed home and told her husband, Fidel, what she saw.

Fidel Delgado said he was skeptical of his wife's claim until the two went to the site.

"I was just stunned," Fidel Delgado said at the underpass Monday morning.

Late last week, the couple, who live near the site, met with their priest from St. Francis of Assisi Church, Obdulia Delgado said. The priest told the Delgado couple that the image should be seen as a positive aspect of their lives, even though other people might be skeptical or poke fun at their claim.

After meeting with the priest, the two felt determined to spread the word of the image and late Sunday about 100 people gathered and knelt in prayer to see for themselves, Obdulia Delgado said.

Some people are taking pictures, inscribing their names and leaving flowers at the scene, but Satanic messages have also been left, WMAQ-TV reported.

"Everybody's amazed. It's hard to begin to believe, but when you see it, it changed something in you. You believe in the faith," Snezna DiLorenz said.

"It's a miracle. It's an image of something ... you can't describe it," Jose Recinos said.

"We're here because the Virgin Mary is on the wall, and she's inside the wall, and we were just curious, but at the same time we're scared, wondering why she's there and what the meaning is of her being there," Annette Byrd said.

Road specialists believe the marking may have been caused by salt or a water mark from expressway above, the TV station reported. Many of the faithful who believe in the marking said it's all in what you choose to believe in.

Police were at the scene Monday to keep an eye on the crowd.