The drive into the desert on the northern edge of Mexico is a bumpy one. Most of the dirt roads are dry and have begun to crumble. The intense midday sun hangs overhead, making it difficult not to squint as we look out into the distance.
On the back of our pickup truck is very precious cargo--water. We're carrying a large black jug filled to the top.
But the water is not for us. We stop by a tree in the desert where a bright blue tank sits conspicuously. On it is printed the word Agua--"water" in Spanish. Our hosts pile out, fill the blue tank, then drive on to their next stop.
What we are witnessing is a twice-weekly routine in the struggle to keep people alive in this treacherous environment. And it is the frontlines of America's immigration debate.
Every day 3,000 Mexican and other Latin American migrants begin the grueling journey on foot through the desert, hoping to make their way to the United States for a better life.
They face heat exhaustion, starvation and severe dehydration. It's impossible for them to carry the amount of water they will need for the days-long trek, and they know that excess weight will make it difficult to dodge U.S. Border Patrol. So they bring only the bare essentials.
The walk is an unforgiving one, and it doesn't take long for them to fall ill. Roughly 300 Mexicans have died so far this year alone, many from a lack of water.
That's why a coalition of community groups in Mexico has established a program called Water For Life. They've placed dozens of large water tanks throughout the Mexico-Arizona desert and use volunteers to ensure they are always full and ready to replenish anyone who needs a drink.
Organizers estimate they've placed 100,000 gallons of donated water in the desert over the past three years, serving untold numbers of desperate migrants.
"Our only objective is to prevent people from dying from a lack of water," says Raul, the director of a Mexican drug rehab centre involved in Water For Life.
With illegal migration such a hot topic in both the United States and Mexico, programs like this can easily be interpreted as defiant political statements. Helping illegal migrants, after all, is a touchy issue on both sides of the border.
But Raul doesn't see it that way. For him, the motivation is purely humanitarian.
"Helping is a goal in and of itself," he explains. "It's not something you do for a reason. These people need help, so we help them. It's as simple as that."
Not everyone agrees though. Water For Life used to leave tanks on the American side of the desert as well, until anti-migrant vigilantes began cutting them open. Organizers decided to remove the tanks for fear the water would one day be poisoned.
Despite this opposition, Water For Life continues its work. Volunteers have even set up makeshift migrant camps throughout the Mexican desert, complete with food, medical care and spare clothes.
For program organizers, the work is never ending.
As we finish filling the tanks and head back to town, we come across a stretch of road with small white crosses lined on either side. We're told they are in memory of Mexicans who entered the desert and never came out.
But Raul and others at Water For Life remain undeterred. While the plight of the migrants is an issue much larger than they can solve, they know that by filling those blue tanks every week, they are doing their part.
"This is a way for us to envision a life bigger than we had before," Raul says. "You have to learn to help others to learn to help yourself."