For 30 years, the AC100 has blazed a trail through the Angeles National Forest, in the backyard of Los Angeles. The 180 or so runners who experience it every year can thank Ken Hamada, the race director and its founder. Hamada was running ultras in the 1980s when most were courses of multiple loops. He wanted a 100-miler that "starts somewhere" and "goes somewhere," and he enlisted friends and volunteers to develop the route and organize the first AC100 in 1986. Much of the trail winds through pine and Douglas fir forest. Some trees are more than 2,000 years old. Other trees are dead and ashen-colored from recent fires, including ones that forced the cancellation of the race in 2002 and 2009. The terrain of the trail -- rocks, tree roots, inclines -- threatens twisted ankles and falls along some steep ledges. Running up and down mountains means greater physical demand than simply a long race. Elevation affects breathing, weather can add impediments and even danger, and the terrain of the trail -- rocks, tree roots, inclines -- threatens twisted ankles and falls along some steep ledges. In addition, there is the challenge of running by the light of a headlamp, all night long. The highest peak on the course is more than 9,000 feet above sea level, nearly the top of Mount Baden-Powell. But it's not necessarily the most challenging stage. Many runners would agree that distinction goes to Mount Wilson, a 4½-mile climb that begins an exhausting three-quarters of the way through the race and is usually climbed under the stars. The foot (and hoof) race that pits humans against horses" That is where the race really begins," explained Hamada. After 75 miles and 20-plus hours of running, "your gas tank is empty, and your hubcaps are spinning off. Then you have to deal a real big challenge: Mount Wilson. And that is really the moment of truth for most runners in the race, because ... there is no easy way out except making it to the finish line.”