Intro:

Competitors could be forgiven if their faces were tenser than usual ahead of the mythical long leg of the 27th Marathon des Sables ("Marathon of the Sands").

Stage four from El Maharch to Jebel El Mraier is 81.5-kilometres (50.6 miles) long and is dreaded by all 821 competitors still left in the race.

Script:

Can you tell what it is yet? Obviously it's competitors illustrating the 27th Marathon des Sables or "Marathon of the Sands".

Stage four from El Maharch to Jebel El Mraier in Morocco is notoriously long, 81.5-kilometres (50.6 miles) in fact, and is dreaded by all 821 competitors still left in the race.

In the men's event, the runner to catch is still Morocco's defending champion Rachid el Morabity, who has won every stage so far.

His achievements have been matched by Laurence Klein in the women's race, who's also on course to defend her title after finishing stage three almost 10 minutes ahead of second-placed Meriem Khali of Morocco.

It's not just the length of the stage that makes it so intimidating though.

Barely nine kilometres in, the field faced the long climb up the Djebel Oftal hill.

At the top, they were rewarded with the most stunning view over Wadi Rheris before encountering the next obstacle - a slope of nearly 20 per cent, although ropes have now been added for the runners' safety.

Once that is overcome all that stands between the runners and the finish line is a river crossing followed by about another 20 kilometres of dunes.

Whilst the best, like El Morabity, will make it to the finish line in around seven hours, some will be spending over 30 hours out on the track.

To top it off, each participant must carry their own backpack containing food, sleeping gear and other material for the whole six days and 240 kilometres (150 miles) of the endurance race.

The camels are just their to taunt them.