Competitors push their bikes up a sand dune during Stage 5 of the 13th edition of Titan Desert 2018 mountain biking race around Merzouga in Morocco on May 3, 2018. The Titan Desert 2018 is 600 kilometre mountain bike race completed over six days, snaking between Boumalne Dades, at the foot-slopes of the High Atlas summits, and Erfoud, an oasis town in the Sahara Desert. / AFP PHOTO / FRANCK FIFE

Competitors ride their bikes during Stage 5 of the 13th edition of Titan Desert 2018 mountain biking race around Merzouga in Morocco on May 3, 2018. The Titan Desert 2018 is 600 kilometre mountain bike race completed over six days, snaking between Boumalne Dades, at the foot-slopes of the High Atlas summits, and Erfoud, an oasis town in the Sahara Desert.

Competitors carry their bikes as they walk, during stage 6 of the 13th edition of the Titan Desert 2018 mountain biking race between Merzouga and Maadid on May 4, 2018. The Titan Desert 2018 is a 600 kilometres mountain bike race completed over six days, snaking between Boumalne Dades, at the foot-slopes of the High Atlas summits, and Erfoud, an oasis town in the Sahara Desert. / AFP PHOTO / FRANCK FIFE

Competitors ride their bikes during stage 6 of the 13th edition of the Titan Desert 2018 mountain biking race between Merzouga and Maadid on May 4, 2018. The Titan Desert 2018 is a 600 kilometres mountain bike race completed over six days, snaking between Boumalne Dades, at the foot-slopes of the High Atlas summits, and Erfoud, an oasis town in the Sahara Desert. / AFP PHOTO / FRANCK FIFE

Competitors ride their bikes during stage 6 of the 13th edition of the Titan Desert 2018 mountain biking race between Merzouga and Maadid on May 4, 2018. The Titan Desert 2018 is a 600 kilometres mountain bike race completed over six days, snaking between Boumalne Dades, at the foot-slopes of the High Atlas summits, and Erfoud, an oasis town in the Sahara Desert. / AFP PHOTO / FRANCK FIFE

Competitors push their bikes along a sand dune during Stage 4 of the 13th edition of the Titan Desert 2018 mountain biking race between Boumalne Dades and Merzouga in Morocco on May 2, 2018. The Titan Desert 2018 is 600 kilometre mountain bike race completed over six days, snaking between Boumalne Dades, at the foot-slopes of the High Atlas summits, and Erfoud, an oasis town in the Sahara Desert.

Two competitors carry their bikes as they walk, to cross the river, during stage 6 of the 13th edition of the Titan Desert 2018 mountain biking race between Merzouga and Maadid on May 4, 2018. The Titan Desert 2018 is a 600 kilometres mountain bike race completed over six days, snaking between Boumalne Dades, at the foot-slopes of the High Atlas summits, and Erfoud, an oasis town in the Sahara Desert. / AFP PHOTO / FRANCK FIFE

Competitors ride their bikes during Stage 5 of the 13th edition of Titan Desert 2018 mountain biking race around Merzouga in Morocco on May 3, 2018. The Titan Desert 2018 is 600 kilometre mountain bike race completed over six days, snaking between Boumalne Dades, at the foot-slopes of the High Atlas summits, and Erfoud, an oasis town in the Sahara Desert.

Competitors push and carry their bikes up a sand dune during Stage 5 of the 13th edition of Titan Desert 2018 mountain biking race around Merzouga in Morocco on May 3, 2018. The Titan Desert 2018 is 600 kilometre mountain bike race completed over six days, snaking between Boumalne Dades, at the foot-slopes of the High Atlas summits, and Erfoud, an oasis town in the Sahara Desert.

A competitor rides his bike during stage 6 of the 13th edition of the Titan Desert 2018 mountain biking race between Merzouga and Maadid on May 4, 2018. The Titan Desert 2018 is a 600 kilometres mountain bike race completed over six days, snaking between Boumalne Dades, at the foot-slopes of the High Atlas summits, and Erfoud, an oasis town in the Sahara Desert. / AFP PHOTO / FRANCK FIFE

A competitor reacts after crossing a sand dune during Stage 4 of the 13th edition of the Titan Desert 2018 mountain biking race between Boumalne Dades and Merzouga in Morocco on May 2, 2018. The Titan Desert 2018 is 600 kilometre mountain bike race completed over six days, snaking between Boumalne Dades, at the foot-slopes of the High Atlas summits, and Erfoud, an oasis town in the Sahara Desert. / AFP PHOTO / FRANCK FIFE