The Horizontes Backyard Ultra in Proença-a-Nova brings the classic Backyard format—created by Lazarus Lake of Barkley Marathons fame—to the rugged landscapes of central Portugal. Runners must complete a set loop every hour, starting on the hour, continuing until only one athlete can finish a final lap alone. It’s a format that rewards patience, strategy, and mental sharpness just as much as raw endurance. The course invites athletes into a rhythm of running, recovering, and lining up again, creating a uniquely tense and communal atmosphere as participants push through day, night, and whatever conditions unfold. Early finishers buy precious minutes of rest before the bell signals another loop, and the cycle continues until the last runner standing claims the win.