On a steep singletrack I hit a rock (I think) went over the bars and bounced down a 40 foot cliff. The bike stayed on the trail. I had to find a way to climb back up there then ride 2 hours back to my car. Broke the helmet in 4 places, compression fractured 3 vertebrae, tore rotator cuff, various scrapes and bruises. That was in 2007. Now I use a dropper seatpost and I'm more careful.