At least 51 people were injured, eight seriously, when lightning struck at a rock festival in western Germany early on Saturday, according to BBC.
Organisers of the Rock am Ring festival, which is headlined by Red Hot Chili Peppers, said lightning hit at 00:30 local time.
The event has now been suspended because of weather concerns.
Central Europe has been hit by severe storms and rain over the past few weeks, leading to 11 deaths in Germany.
Police told German media two people had to be resuscitated after Saturday's incident at the airport in the town of Mendig, about 100km west of Frankfurt.
The Rock am Ring festival - one of the most popular of its kind in Germany - also suffered lightning strikes last year, when 33 people were taken to hospital.
The festival website warned fans of the possibility of strong rainfall and thunderstorms on Saturday evening.
The organisers of Rock am Ring, now in its 31st year, initially said this year's event would continue, and that clear weather was expected for most of the day on Saturday. It was due to have finished on Sunday.
Red Hot Chili Peppers are among several bands, including Foals, Deftones and We Are Scientists, which had been expected to perform on Saturday. Some 92,500 people were due to attend over the course of the weekend.
Last weekend, 35 people were injured, three seriously, when lightning struck a football match in south-west Germany. A further 11 people were hurt by a lightning strike in a Paris park where a children's birthday party was taking place.