A marathon race held in Sweden, coordinated by several companies from Sweden and the UK, set a new Guinness World Record for the deepest underground marathon, surpassing 1,000 meters underground.
According to a report from the Guinness World Records website on March 11th, the record-breaking marathon race was organized by UK-based BecomingX and ICMM, together with Sweden’s Boliden, and took place in Garpenberg, Sweden on October 25, 2025.
A total of 55 participants from 18 countries raced on a track located 1,118.56 meters underground, breaking the previous record for the deepest underground marathon.
The previous world record was held by the Crystal Mine Underground Marathon in a salt mine 500 meters below sea level in Thuringia, Germany.
For this challenging event, participants had to wear headlamps to navigate the underground track. They completed 11 laps, raising approximately $1 million for charity during the process.
This event also earned them a second world record title for the farthest underground marathon distance (team), with a total distance of 1,082.30 meters.
Due to the deep location of the track underground, it took participants a full 3 minutes by elevator to reach the starting line from the surface.
Participants described the difficulty of the race. One runner said, “Even stopping for 3 minutes felt like a long time.”
Another participant commented, “The weather was hot, humid, and dusty, but we were all doing well.”
One runner described most of the course as uphill, while another remarked, “No one has ever run this deep underground before.”
Bear Grylls, co-founder of BecomingX, stated, “Running a marathon in such an impromptu environment is very challenging. When you enter such an environment, you feel fear, adrenaline surges, and the pressure of the environment, which undoubtedly adds a lot of difficulty.”
The marathon is an official Olympic competition, with a standard length of 42.195 kilometers established by World Athletics in 1921.
According to Guinness World Records, Belgian woman Hilde Dosogne ran a marathon every day in 2024, totaling 366 marathons in a year, setting the record for the longest consecutive days running marathons (female).
Dosogne covered at least 15,444 kilometers in that year. As a bioengineer at a chemical company, she woke up early every day to make time for marathons in the afternoon.