Unpacking the 200-mile phenomenon.
The Selvaggio Blu wends 25 miles along the east coast of Sardinia, over cliff faces and in between beaches.
The stories behind some of the craziest moments at this year's Hardrock 100.
The Harvey Manning Peak Challenge saw its first finishers, Ras Vaughan and Seth Wolpin. It took them 78 hours 36 minutes.
At the 2017 Bighorn 100, only 47 percent of the starters finished. Four of them did so hand-in-hand.
A volunteer's perspective of the rugged, technical Escarpment Trail Run through New York's Catskills Mountains
A miscalculated interaction with a black bear provides useful lessons on how to react to large predators on the trails.
6 surprise stories at the 2017 Western States 100
Jim Walmsley is hoping to make amends for last year's wrong turn at Western States
Breast-cancer survivor Alison Chavez runs at the back of the pack, but she is a champion.