Hundreds have tried but only 15 people have ever been able to finish the Barkley. For many years since its beginning, no one had finished and many wondered whether its founder, Lazarus Lake, had created an impossible challenge.
Lazarus Lake (real name Gary Cantrell), came up with the idea for this race after hearing about the 1977 escape of James Earl Ray, the assassin of Martin Luther King, Jr, from nearby Brushy Mountain State Penitentiary.
Ray escaped the prison and covered a mere 13km (8 miles) in 55 hours of running through those woods. Lazarus Lake heard the story and thought: "I could do at least 100 miles", and so the race was born. Barkley is actually Lazarus Lake's longtime neighbour and running mate, Barry Barkley.
So what makes the Barkley so hard? Well, where do we even begin? The course that doesn't really exist, for example. The mind games the race director plays on athletes. There are a number of factors that, combined, make the Barkley the most gruelling race on the planet.
While we can all name a number of famous athletes with a collection of impressive accomplishments, it is unlikely that any of them could finish the Barkley. One of the most interesting things about that race is precisely the type of people it attracts. In previous years, Barkley finishers have not necessarily fit the stereotype of athleticism and, in many ways, this race is redefining it.
10 facts about the Barkley Marathons
• No one really knows when it begins, right up to a few hours before it begins.
• Runners have to complete the 160km (or thereabouts) route in 60 hours. There are 5 loops in total and no loop is the same with runners going clockwise and anti-clockwise, in daytime and through the night.
• Race director Lazarus Lake starts the race the old traditional way: by lighting up a cigarette.
• There is no marked course. Runners can try drawing their own maps from a master map and have to then pick up pages from books hidden on the course, to prove they did the full loop. The books are mind games on their own, with titles relating to punishment and suffering.
• It's actually a lot more than 160km. No one really knows how long, it kind of depends on how the organisers are feeling when they decide the course. Participants believe it's actually closer to 210km.
• The route goes around (and under) Bushy State Prison, a former maximum security prison.
• Only 15 people have ever finished the race.
• It costs US $1.60 to enter. However, first you have to figure out how to enter. If you're a newbie runner, you also have to give Lazarus Lake a license plate from your country. All entrants must also take one item that Lazarus Lake asks for (flannel shirts, white shirts, whatever he fancies at the time).
• It is tougher than climbing Mt Everest. Over the course of the five loops that make up the full race, runners climb a total of 16,500m – twice the elevation of Mt Everest.
• Completing three out of the five loops means finishing a "fun run". However, that "fun run" is still more than 100km long and more than the elevation of Mt Everest so there's probably very little "fun" about it.
To keep up with this year's race as it happens this weekend, head to Twitter, where co-organiser Keith Dunn is posting occasional updates.
For more on the Barkley Marathons, watch the 2014 documentary on Netflix and this more recent documentary on the race Where Dreams Go To Die, starring Gary Robbins, a Canadian who this weekend is attempting Barkley for the third time.
