The Barkley Marathons consist of five 20-mile loops (although sometimes they tend to be longer) within Tennessee's Frozen Head State Park. It’s arguably one of the toughest ultramarathons in the world and just 14 men had previously finished the 100-mile race under the 60-hour cut-off.

The race garnered fame after a documentary with the ominous subtitle “The Race That Eats Its Young” was released in 2016. In addition to its 60,000 feet of elevation gain, which adds to the physical difficulty, the race has its fun quirks. It is limited to 40 runners through a secretive race registration process that includes a $1.60 entry fee and requires runners to bring a license plate from their home state or country. There’s no official start time but it can go off at any time from midnight to noon on the designated race day. A conch is sounded to signal one-hour until the start and then the race begins when a cigarette is lit by race director Gary “Lazarus Lake” Cantrell.

Participants have to locate pages from books that have been scattered throughout the park. This ensures that the participant followed the race map. Each runner is given a race number to correspond with the book’s page that they need. Competitors get a new race number and a new page requirement for each lap. There are no aid stations or markers so runners must follow a map that is provided the night before the start.

The 2017 edition of the race started over the weekend and the 60-hour cut-off was set for 1:42 p.m. ET Monday.

John Kelly, a Washington, D.C. resident, became the 15th finisher in race history by completing the race in 59 hours and 30 minutes.

Gary Robbins, a runner from North Vancouver, B.C., was not so lucky. He reached the finish line just six seconds over the 60-hour cut-off time. He was unable to locate the finish and headed in the opposite director before he realized his mistake. Robbins collapsed at the finish line with all the required pages.

Watch Robbins' finish (via Canadian Running):

When a runner is unable to finish the race, a bugler plays “Taps.” Never has it sounded more bitter.

- Chris Chavez