#1 Alonso vs Raikkonen
One of the scariest crash in Formula One history could be this crash involving the former world champions Kimi Raikkonen and Fernando Alonso during the 2015 Austrian Grand Prix. The Finn lost the control of his car after the turn 2 in the opening lap at Speilberg, swerved into Alonso, whose Mclaren ended up on top of his Ferrari. Raikkonen's wheelspin caused an uncontrolled left steer crashing Alonso's Mclaren, lifting it up over the Ferrari dragging it till the barrier halt.
The crash was so severe that it was lucky to see both the drivers unscathed. McLaren's onboard camera got damaged during the crash and so wasn't available for replays. Raikkonen's onboard cam and a long shot camera weren't sufficient to see the scenes behind the crash. Post race Alonso felt that the use of prime tires instead of supersofts could have been the reason for Raikkonen to lose the control. Stewards declared that no driver was at fault after investigating the clash.