The Marathon des Sables (Marathon of the Sands) is a six-day, 254 km (156 mile) ultramarathon, which is the equivalent to six regular marathons. The longest single stage (2009) is 91 km (55 miles) long. This multiday race is held every year in the southern Moroccan desert. It is considered the toughest foot race on Earth. The first event of the Marathon started in 1986. Competitors must carry all personal belongings and food for the entire event in their backpack. Water and tents are supplied by the organizers. Some of the 1013 competitors compete in the 25th edition of the gruelling 150-mile Marathon des Sables in Irhs Valley, some 186 miles from Ouarzazate in Morocco on April 4. The race includes a full marathon on one day, and a 55-mile stage, as well as others of varying length and terrain during seven days. Competitors must carry all their equipment on their backs. Only a carefully rationed nine litres of water and open-sided local tents are provided daily by the organizers. Competitors come from 43 nations and range in age from 16 to 73.