Officials in the US state of Wisconsin are investigating how eight people were trapped upside down on a roller coaster during a festival; some of them for more than three hours.
The coaster cars became stranded near the top of a loop at around 1:30pm Sunday at Crandon International Offroad Raceway.
Rescuers arrived to find eight passengers hanging upside down by their seat belts.
Firefighters used ladder trucks to reach them, securing each before releasing their over-the-shoulder safety bars, the Crandon Fire Department said.
It took almost three and a half hours to get all the passengers off. One person was taken to hospital.