Four people were injured and dozens trapped when a roller coaster derailed at the Six Flags amusement park in California.
The rescue operation took over three hours to complete.
Two people were brought to hospital for minor injuries after a tree branch apparently got caught in the ride's crosshairs causing the roller coaster to derail.
The "Ninja" ride has been closed following the incident.
According to the Six Flags website the "Ninja" is known as the "Black Belt of Roller Coasters" and is one of four of its kind in the US.
Its top speed is 55mph and "pivots with precision" as those on board "narrowly miss tagging land and water" as it whips through its course.
