On October 25, 2025, a unique athletic feat took place 1,120 metres below sea level in Sweden’s Garpenberg Zinc Mine. Organized through a collaboration between BecomingX, the ICMM, and Boliden, this extraordinary event challenged 55 runners to complete a full 42.2km marathon within the subterranean environment. Despite the grueling conditions, which included high humidity and temperatures reaching 28°C, the race proved successful, resulting in the establishment of two new Guinness World Records.
