We interviewed the legendary Yiannis Kouros before his legendary 24-hour world record that had stood for nearly 24 years was broken. Hear how he doesn't believe in training year-round or in doing long runs.

The great mountain/trail runner Kilian Jornet ran the first track race of his life on Friday, taking a stab at Yiannis Kouros' legendary 24-hour world record. He ended up in the hospital after less than 11 hours of running.

Can we name a single person as the greatest ultra runner in history? Yes, we can for the women, but not for the men.

Kouros holds the #1 ultramarathon record in the books - the men's 24 hour record of 188.68 miles (303.506 km).

There's no world record easier to understand in the ultramarathon world than, "How far can you run in a day?" And there's been no human in history that has come anywhere close to Yiannis Kouros in a 24 hour period.