In the world's hottest, driest environments, humans, like all other animals, face the greatest challenge of all - the quest for water. Humans can survive for weeks without food, but only days without water, as the second episode of Human Planet reveals. John Hurt narrates, as we see a man in Mali battle through a sandstorm to get his cows to a remote lake - only to see desert elephants have arrived there first and are hoarding the place. Tubu women and children navigate the dunes of the Sahara in search of an oasis, and at the height of a drought, 2,000 men rush into Antogo Lake to catch the fish trapped by the evaporating water. For the Wodaabe people the arrival of desert rains means flowering and food - and a chance for new love. They come together to dance and party in search of a new partner. But, in Niger, it's the men who pretty themselves up and the women who choose.