USA. Arizona. Tucson. Wednesday, January 9, 2019. Given the staggering length and ruggedness of the journey, it is physically impossible for anyone attempting to cross the border on foot to carry enough water and food supplies to survive. In the words of Gerardo Campos, a humanitarian worker in remote parts of the border: "They may have an idea that they're going to be walking for just a couple of days, as they've been told by the coyotes to hook them and make their money. But they don't realize until they're into the desert that it's not two days. It's going to be about five, six, seven, ten days walking.