Alfa Romeo driver Zhou Guanyu's Alfa Romeo flipped upside down following a collision with Mercedes' George Russell at the start of the British Grand Prix.
Carlos Sainz was in pole position at Silverstone but had been overtaken by world champion Max Verstappen when the frightening crash took place behind them.
Russell appeared to be hit from behind at the start and was knocked into Zhou, whose car went flying across a gravel trap and over a tire wall into the retaining fence. The car was skidding on the “halo” which protects the driver's head.
Russell, who ran from his car to help Zhou, called it “one of the scariest crashes I’ve ever seen".
Alpine's Esteban Ocon limped back to the pits on three-and-a-half tyres, with the half flailing on a rim.
F1 governing body FIA said Zhou and Williams driver Alexander Albon were being medically evaluated but were both were conscious. Albon had spun into the pit wall.
The Alfa Romeo team said in a statement: "Zhou is conscious. There are no fractures. Considering the circumstances, he's pretty well."
The FIA also said that Mercedes driver Russell was not allowed to restart as he received mechanical assistance during the race.
“I’m glad to see Zhou okay. It was an horrific incident,” Russell told Sky Sports.
“I jumped out of the car to see that Zhou was ok. When got back to car I couldn’t restart it. As soon as you get outside assistance you cannot restart the race.”
You can see images from the crash in the gallery above. To move on to the next image, click on the arrows, or if you're using a mobile device, simply swipe.