There is little left for Kilian Jornet to accomplish as an ultrarunner. He has won the most prestigious and grueling trail and mountain races in the world multiple times, including the Hardrock 100 four times and the Ultra-Trail du Mont-Blanc three times.

In May 2017, Jornet scaled Mount Everest, completing his Summits of My Life project. A new documentary on the attempt, Path to Everest, is out now. The film goes behind-the-scenes as Jornet worked toward setting the fastest known times for ascent and descent on the world’s most famous peaks.

He recently spoke to Runner’s World about why he took on such a feat, where he finds his limits, and why he feels uncomfortable in cities.

Gear up Like Kilian Jornet
Salomon Ultra Pro Trail-Running Shoes
Salomon Ultra Pro Trail-Running Shoes
$150 at REI
Salomon Pulse Mid Aero Jacket
Salomon Pulse Mid Aero Jacket
Suunto Adult Ambit3 Peak Watch - Sapphire/One Size Fits All
Suunto Adult Ambit3 Peak Watch - Sapphire/One Size Fits All
Headshot of Derek Call
Derek Call
Video Producer

Since becoming a video producer for Runner’s World in 2014, Derek has captured such historic moments as Meb Keflezighi and Desiree Linden’s Boston victories and Amy Cragg’s win at the 2016 U.S. Olympic Marathon Trials, and Galen Rupp and Shalane Flanagan breaking the tape in Chicago and New York, respectively.