The Grand Raid de La Réunion, known as the Diagonale des Fous, is one of the most challenging ultra-trail races in the world. Spanning 165 kilometers with over 9,500 meters of elevation gain across the volcanic island of Réunion, this race tests the limits of human endurance. Baptiste Chassagne's account takes us through the preparation, strategy, and mental fortitude required to tackle this legendary course. From the pre-dawn start in Saint-Philippe to the grueling climbs through tropical forests and across volcanic ridges, every step presents a new challenge. The race is not just about physical preparation; it's about understanding the terrain, managing nutrition, and maintaining focus through sleep deprivation and extreme fatigue. Baptiste's story captures the essence of what makes this race so special to the trail running community.