While most 15-year-old boys are on their way to school in the morning, Julio Cesar Gutierrez is on his way to work.
He toils inside the Cerro Rico, or "rich mountain" of Potosí, for the fabled Bolivian silver that looms at the peak at the Andes mountains, dominating every view of the highest city in the world. It is the oldest mine in the Americas and one of the oldest working mines in the world.
It is also one of the most dangerous.
The entrance to the mine is muddy, with a sloping ceiling. At 15,000 feet above sea level you have to work to take in each breath.
Gutierrez took ABC News into the mine with his older brother Luis Alberto and some other boys. It was a daunting tour inside what truly is a hell on Earth. An estimated 20,000 people work each day, including 1,000 children.
Inside there are no lights except for the workers' head lamps, and there is no ventilation, or safety equipment. Often there is just one exit; if a shaft collapses there is no way out.
Gutierrez began working outside the mine when he was just 6 years old; he's been working inside since he was 12.
"I hate it," he said in Spanish. "It's very dangerous for children."
Potosí may be the most important place in the history of the modern world that most people have never heard of. The Spanish discovered silver in Potosí in 1545. The mine was so rich that historians say its wealth single-handedly fueled the Spanish conquest of the Americas. They call it "The Mountain That Eats Men."
It is estimated that 8 million American Indian and African slaves died in forced labor at the mine. Amid the colonial remnants of what was once a magnificent city sits the massive Spanish royal mint, now a museum that shows just a fraction of the mother lode that made this remote mountainous place the largest city in the world by the year 1650. And the richest.
And yet all that is left behind is poverty, a poverty of such extreme desperation that it sends men and boys into the 400 mines burrowed into the mountain's belly to scratch out the most meager of livings.
While technically the mines are owned by private companies, in reality there are no owners. They are run as cooperatives.
Fernando Vasquez, director of social management for Bolivia's Cooperative Mining Sector, told ABC News the coops need a lot of investment to improve safety conditions.
In this, the poorest country in South America, there are no safety inspections of mines. The government does, however, provide guidelines and seminars to promote safety.
In the end, Vasquez says safety is solely the responsibility of each mining company or cooperative, which is why what we saw inside looked almost medieval: no safety gear, no power, no ventilation.
The boys told us to run through one section with broken beams overhead, knowing it could collapse at any moment. We heard the distant sound of drills as we wound our way through the snaking tunnels and narrow shafts.
John Trew, senior technical adviser on child labor at the charity CARE USA, traveled to Potosí to talk to us about CARE's work there. He has traveled the world studying child labor and trying to improve conditions for children, and he is horrified by what he sees here.
He says it is "by far the worst" of the child labor conditions he has seen. "It is truly one of the worst hazardous experiences of the environment, which children can be faced with -- not just from the short-term hazard that they face but the long-term health consequences."
Gutierrez makes about $2.50 at the end of each day. Like thousands of families, his family is trapped in a cycle of poverty. The child miners of Potosí start young and the die young. Most don't live to see 40.
Gutierrez's father is still alive. Like almost all of the veteran miners his lungs are in poor shape after years of breathing the dusty mine air without safety masks. He can't work in the mines, so his three sons must. It has been like this for generations.
"Children in many cases supply the income that allows people to meet their basic needs just to survive," Trew said.
Gutierrez's mother, Doña Alejandra Caleapa de Gutierrez, struggles to keep food on the table. Each morning while her boys head to the mine, she prepares lunches she hopes to sell to other miners at a tunnel entrance to make a few extra dollars.
As Gutierrez leaves the modest cinder block house on dirt hillside overlooking the colonial city, he pauses at the gate to bless himself. He lives in fear of the day ahead.
His mother told us she worries every day when her son leaves for the mines. "It makes me so sad to see him working there," she said in Spanish, tears running down her cheeks. "Anything could happen, it is so dangerous."
The day we met Doña Alejandra she learned that her oldest son had been injured when a rock slab fell on him in the mine.
"I don't want my boys to work there. I worry more than anything about them. I want them to have a steady job, to be secure."
But in the highest city on Earth, in the poorest province of the poorest country in South America, there is only one option for most families: the mine.
Early each morning the miner's market buzzes with activity as the men and boys search for essential supplies: food, head lamps and dynamite that sells for 25 cents a stick. There are crude safety masks for sale for about $12 but few wear them. They're expensive, but a lack of safety awareness also seems to allow miners to think that things like breathing masks are unmanly.
Gutierrez says sometimes when he's in the mine he can feel the deadly dust going inside his body.
"I feel dizzy," he said, "as if I am going to faint. Sometimes we tie a handkerchief around our mouth so we don't breath it in."
Gutierrez and his brother are used to thin air at this altitude, but the miners never get used to life inside the mine, at least not without help from the coca leaf. Coca is the fuel that has kept this mine running for all these centuries. It comes from the lowland valleys of Bolivia. The leaf has to go through a complex chemical process to become cocaine, chewed raw it is simply a stimulant that suppresses hunger, fear and fatigue.
Gutierrez says he couldn't do the job without coca. "If you don't use coca, you can become anxious inside. You can become weak. Coca keeps you up even if you work all night."
Inside the mine they're not looking for silver anymore; they'll settle for scraps of tin and other minerals. The tools they use have hardly changed since the Spanish conquerors left: hammers and picks. There are drills much deeper in the mine, but Gutierrez doesn't use them.
After traveling just half a mile inside the mine the closeness of the air, the withering humidity and the instability of the rocks become unbearable.
Gutierrez wanted us to go 45 feet down a hole to the next level while dangling from a thin rope.
"How many exits are there," I asked as I looked down a dark hole with no ladder on the side. "It is the only way in and out," he said.
Deep inside the remote mine, with no safety equipment and facing a deep, dark vertical shaft with no exit, we said no. The risks seemed overwhelming.
So instead they took us to another area where they are mining.
They lift rocks in a canvas bag using a crude winch. The stifling heat is overpowering so the men and boys often go shirtless, the dust coating their skin.
As the youngest in the group, Gutierrez gets the most menial of tasks: lugging heavy rocks from one place to another.
"It's twice as hot when you go deeper," he said.
He is not yet ready to work with dynamite. For now, that is reserved for the older boys and men. "You have to learn how, before you can work with it," he said. But Gutierrez isn't sure that he wants to learn how.
"It's very dangerous for me and anyway, the sound is so powerful; I know dynamite can kill you."
Gutierrez's brother Luis Alberto started working in the mine when he was 15 years old. He is now 21.
"Sometimes it can be very dangerous," Luis Alberto said, "because the dynamite moves everything and things can fall."
They all know people who have died in the mine from blasts, collapses or poisonous air. Miles deep in the mine, farther than we could go, the conditions are intolerable. It's oppressively hot. Dust fills the air, and the lungs.
Back on the surface on the slope of the mine sits the new community center built by CARE USA.
The focus is on women and children. Mothers are seen to be the key to changing the culture. They are taught crafts and other skills that help bring in a few extra dollars. Gutierrez's mother hopes that with CARE's help she will find a way out of poverty and a way to keep her sons out of the mines.
For the children there are activities and classes. There are games and remedial classes for older boys like Gutierrez.
"Unless the community or a parent or teachers or families begin to think that a problem exists there is nothing that CARE or anybody can do anything about it," Care USA's Trew said. "What we are talking about is incremental successes, small successes moving them from less hazardous conditions into more appropriate conditions for their ages or for their mothers."
CARE is working to improve the desperately underfunded school system in Potosí. At the school we visited we didn't see a single computer.
Incredibly, Gutierrez tries to juggle high school classes with a full shift in the mine.
He told us that sometimes he doesn't get home from the mine until 2 a.m. but he is still passionate about school. English is his favorite subject.
"I would like to be going to university," he said when asked about his dreams for the future. "I hope I'm not working here anymore."
He wants to be a civil engineer. That is a dream. For now Gutierrez is happiest at the end of each day when he's leaving the mine and sees that light at the end of the tunnel.
He knows that he has survived another day of hard labor.