It was supposed to be a great day at the races for fans of IndyCar racing. The Grand Prix of Houston was in its final lap on what was a gorgeous day at Reliant Park in Houston. But then, disaster.

A crash involving one of IndyCar’s most popular drivers, Dario Franchitti, marred the afternoon.

The crash occurred on the final lap, when the three time Indy 500 winner collided with another car. Franchitti’s car went careening into the stands, giving race fans little time to get out of the way.

“The car was up in the air and in the fence before you could even respond,” witness Gary Johnson told Local 2, KTRH’s television partner.

“It just shattered like glass. It went everywhere. It was like something exploded,” witness Paul Lock told said.

 As many as 15 people were hurt, including Franchitti and a teenager. Gary Johnson saw the whole thing unfold right in front of him.

“A kid was hit in front of me. He was hit in his lower back and had scratches on his shoulders,” Johnson said.

Another witness summed it up by saying, “It was upsetting to see that.”

Eleven fans were treated on site at Reliant Park. Two more fans were taken to Memorial Hermann hospital, as was a race official. They are listed in good condition. Franchitti suffered a concussion, two broken vertebrae and a fractured ankle. He had surgery and is listed in fair condition.