Any 24-hour sports car race is bound to have its share of accidents and incidents. However, last week's Nürburgring 24 Hour race was especially chaotic due to the rain, hail and resulting icy conditions on the track. Interestingly, the crash you're about to see happened while the track was dry.
From what we've read, and what we can see in this very short clip, the two cars (both from the Black Falcon paddocks) made contact with a little more that 7-hours remaining in the race. It happened somewhere on the track between the Planzgarten and Schwalbenschwanz sections (a nearly 1-kilometer fast section of the track with longish straights and easier turns before coming to the more serious corners of the Schwalbenschwanz.
There was no live coverage of the accident, however at least one spectator had their own camera rolling and captured the moment of impact and resulting carnage as it unfolded right in front of them. It appears as if the Mercedes was overtaking the much slower Porsche on the inside as the Porsche began to turn into the corner (the cars were most likely in much different classes). As the Porsche was pushed into the guardrail, the contact was violent enough to flip it over and send it careening down the grass on its roof. I've watched the video over and over and I'm still amazed that apparently neither of the drivers were seriously injured from the accident.