The Barkley Marathons is an ultramarathon held annually in the rugged terrain of Frozen Head State Park in Tennessee. It was created by Gary Cantrell, also known as "Lazarus Lake," and features a challenging course of approximately 100 miles, though the exact distance is intentionally ambiguous. Runners must navigate through difficult trails, steep climbs, and unpredictable weather conditions. Participants have 60 hours to complete the race, which includes five loops of about 20 miles each. The event is notorious for its low finish rate, with only a handful of runners successfully completing it since its inception in 1986. The Barkley Marathons is often regarded as one of the toughest endurance races in the world.