A last-runner-standing ultramarathon based at the Garañón cabins near Roque Nublo. Up to 150 runners start a 6.706 km loop every hour and must complete it within sixty minutes to remain in the race. The event supports the work of Asociación Kilómetros por Sonrisas against childhood cancer and rare diseases.

There is no predetermined finishing distance: another loop begins on the hour until only one athlete can complete it within the limit. The high-altitude base stands at roughly 1,720 metres, with views towards Roque Nublo, Roque Bentayga and, in clear weather, Mount Teide.