You've probably heard of long footraces that require great stamina, called "marathons." But these 42-kilometer-long races are what Americans call a "piece of cake" compared to what one newspaper describes as "the world's most daunting footrace."

It's the "Barkley Marathons," marathons, plural, because each year there are two events: one covering 160 perilous kilometers, and a "fun run" of a mere 100 kilometers or so. Some fun!

The featured race involves five trips around the same course; two of them run in reverse! Each 32-kilometer leg must be completed in 12 hours or less, or you're disqualified.

That sounds grueling, you say, but maybe not unbearable for someone who's really fit and determined.

Think again. The course, which skirts a mountainous park in the southern state of Tennessee, sends runners over dirt roads, high-grass meadows, flinty inclines, and thickets that must be hacked clear to get through. In each of the five laps, contestants face 13 separate climbs totaling 3,000 meters.

In the way lie briers and thorns, fallen logs, blood-sucking bugs called chiggers, babbling brooks that can change to raging torrents in thunderstorms, and the occasional snake. The only first aid posts are two unmanned water stations, six or more hours apart.

The course has no markings. Runners are handed a crude map that pinpoints the location of nine or more books placed along the way. The competitor must tear a page out of each of them to prove he or she was really there. This year, the organizer put one of the books at the mouth of a rattlesnake hole.

So who won the main Barkley Marathons race this year? No one. No one even finished -- which is not unusual. Over 11 years, only six runners have ever completed the race.