Runners strap headlamps on to tackle deepest marathon over 3,000 ft underground

The record-breaking marathon was a joint venture between BecomingX (UK), ICMM (UK) and Boliden (Sweden), and took place in Garpenberg, Sweden, on 25 October 2025. The team ran 11 laps around the route and raised around $1 million for charity in the process. The event also earned them a second world record title for deepest underground marathon distance run (team) with a total of 1,082.30 m (3,550 ft 10 in).