Family vacation in Michigan and just happened to find a bike race. Expert course was 4 laps at Boyne Mountain ski resort xc trails. Trails were in perfect shape with some really fast flowy sections and then some hard climbing. On my third lap, I missed the entrance to a plank bridge over a mud bog. Over the bars into the mud bog. I got up onto the bridge, jumped on the bike and realized my chain had come off.......off the bridge and over the bars I went again for the second time within 20 seconds. 4th place, missed the podium in my group by 2 minutes