Sahara race tests athletes' limits

Runners will cross 230km of desert

By the BBC's Frank Gardner

Hundreds of athletes in Morocco have set off on one of the world's toughest endurance races.

The annual seven-day Marathon of the Sands has drawn a record 700 competitors this year.

It is not for the casual athlete - the race is on foot and covers 238km (149 miles) of desert.

Only endurance athletes need apply

The competitors taking part in this race through the Sahara Desert can look forward to seven days of hell.

Soaring temperatures, blinding sun and a chance encounter with a venomous snake are just some of the features of this annual endurance race.

Competitors must carry their own food, sleeping bag and even a pump to suck out the poison if they are bitten by a snake.

The only support they can expect from the organisers is the daily nine litre ration of water and an open-sided Berber tent to shelter in at night.

Oasis: Runners will find precious little shade

The race is held in six stages, starting in the Moroccan oasis town of Ouarzazate.

The terrain is a confusing mixture of soft sand and hard gravel, with the occasional oasis to offer some shade.

With temperatures in previous races having risen to 50C, competitors say their biggest fear is dehydration.

But getting lost can be a problem too.

Since the race was first held in 1986, the most infamous story remains the man who disappeared for 12 days in 1994.

He was found eventually still alive 400km away in Algeria.