Marathon des Sables

The Marathon des Sables (MdS) is a 6-day, 251 km (156 mi) ultramarathon through the Sahara Desert in southern Morocco. Dubbed 'the toughest footrace on Earth,' competitors carry all their own food and gear in a backpack, sleeping in open Berber tents each night. Temperatures regularly exceed 50°C (122°F). Stages range from a marathon distance to an 86 km (53 mi) overnight double marathon. The race has run annually since 1986, attracting ~1,300 competitors from 50+ countries. Runners over 50 make up a significant and growing portion of finishers — the oldest finisher was 78. Training demands ultra-distance running, heat acclimatization, self-sufficiency skills (competitors carry everything except water and a tent), sand and terrain adaptation, and nutrition strategy for multi-day effort.