A competitor cools down at a checkpoint while taking part in stage 4 of the 33rd edition of Marathon des Sables, in the Sahara desert, near Merzouga, southern Morocco, Wednesday, April 11, 2018. Under a hot desert sun and with the desolation of the Sahara all around, about 1,000 competitors from 50 countries took part in this year's Marathon des Sables, or Marathon of the Sands. (AP Photo/Mosa'ab Elshamy)