The ring was a dangerous track on so many levels that it was finally retired from formula racing after being the center of German racing and race testing for decades. Racers would spin off the track, crash, and be laying in a crumpled car, soaked in fuel from the now punctured fuel tanks that would surround the drivers of that era. There were sections were you were a mile or so from a race official, so your crash would be difficult to locate and the search would start late.
Also, the track is notorious for the several spots where the race cars would catch air, losing all contact with the road, including in the middle of the longest straight when the car is near maximum speed. At the end of this straight there is a hump in the road right at a gentle curve that goes under a bridge, requiring a throttle lift to negotiate properly at speed. Cars would also bottom out in many sections, so they were set at a very high static ride height
This course had over 170 turns in its 14 miles, and the number of straights you could count on one hand (using decimal, not counting to 31 on one hand). It is also far from flat, with nearly 1000 feet of altitude change in a lap.
When the F1 cars went to 3 liter engines, the 'Ring started to "become an air show". Laptimes dropped below 8 minutes, then 7, but the crashes were too frequent and drivers complained of the danger en masse. The F1 circus went to Hockenheim while they planed the humps and straightened the curves, but crashes were too frequent and severe, and the big 'ring is no longer raced on that level.
This track is available in the fantastic race sim Grand Prix Legends, which is set in the 1967 season, which was the return season for the 3 liter engines, and the last season that cars did not have aerodynamic effects.