Four teenagers were airlifted to hospitals Tuesday afternoon after two cars on one of England’s best-known roller coasters collided, stranding passengers 25 feet off the ground.

The collision happened just after 2 pm local time on The Smiler roller coaster at Alton Towers, an amusement park located 150 about miles north of London. According to Sky News, a car carrying 16 passengers crashed into an empty car in front of it.

One witness tweeted that there was “blood everywhere” and that passengers were knocked unconscious.

The four teens—two boys and two girls—“suffered serious leg injuries in the incident,” according to Steve Parry, a spokesman for West Midlands Ambulance Service. Parry told Sky News the other 12 passengers were not seriously injured.

Ian Crabbe, director of Alton Towers Resort, said the accident is under investigation. The crash is reportedly the seventh time The Smiler has been forced to close for repairs since it opened in July 2013, including one incident in November 2013 when the ride’s wheels fell off and struck several passengers.

Other than that, everyone had a fun day at the park

Image via Sky News. Contact the author at taylor@gawker.com.