B.U.T.XxX - Burgbernheim Ultra Trail is an ultra race in Burgbernheim, Germany, held at the foot of the Frankenhöhe as an end-of-season challenge. It features two distances based on a 10 km loop: 50 km (5 loops) and 100 km (10 loops). The race format is demanding: each loop has a two-hour limit, new loops commence every two hours, and participants missing a start window or failing to begin the next loop are disqualified. The 100 km runners start before dawn, followed by the 50 km field, with both groups completing their final lap after dark. Victors are determined by the shortest cumulative time, emphasizing speed despite the stop-start structure.
Each loop includes 344 meters of elevation change, accumulating significant vertical gain for the 100 km distance. The course winds through trails in the Frankenhöhe's orchards and forests, incorporating former motocross tracks, a ski slope, and old stairways to create challenging, uneven terrain. Organizers characterize the event as intensely difficult and competitive. Runners can gather by the campfire and utilize the runner buffet, which offers vegan choices, between loops, providing a social aspect without compromising the race's rigor. The event targets experienced ultra runners and newcomers seeking a final demanding race before the ultra season concludes.