The eight-car pileup happened at approximately 4:30 p.m. and blocked the intersection of West Congress Parkway and South Wells.
Witnesses said one of the cars went airborne before landing on its side.
12 people were rushed to area hospitals. 11 others refused treatment.
"I was turning onto Congress from Wells, just made the turn, and I look to the left and all of a sudden there was a rainstorm of parts from an automobile coming at my car with oil and water," said a driver who witnessed the aftermath of the crash. "I didn't know what was happening."
Damaged cars were still scattered around the intersection Saturday night. The cause of the crash is still under investigation.