I am not writing this from Bolivia. But in my mind, it is 2002 and I’m in this landlocked country, on a five-week research trip for The Rough Guide to South America.

It was my first travel writing gig, so I rushed from the Amazon to the Altiplano, trying to cover as much ground as possible. There were moments, admittedly few, when I did manage to stop, breathe the high-altitude air and take in the world around me. Yesterday, an article in National Geographic, Bolivia’s New Order, brought those moments back to life.

There was a particular afternoon in Potosí, the highest city in the world, when a couple of miners instantly befriended me. They took me to the nearby village of Tarapaya for a swim in El Ojo del Inca, a small volcanic pool with balmy green water. My new friends warned me not to swim to the center of the pool due to a mysterious force that pulls people in. So I floated close to the edge.

I felt most connected to Efrain. He was 26 and had a sincere ear-to-ear smile. He had worked in the mines since the age of 14 – and he was proud of it. Now, his job was to take tourists into the mines for an agency, Koala Tours, owned and managed by ex-miners. He asked if I’d like to join one of his tours. It wasn’t an easy “yes” but I had to see what Efrain was so proud of.

The next day, we made our way to Cerro Rico, the mine that made Potosí the richest source of silver in the world back in the 17th century. Now, it’s an utterly desolate landscape, almost post-apocalyptic. There isn’t much silver leftover; these days it’s mostly tin.

What took place over the next couple of hours, as we descended deeper and deeper into the pitch-dark mountain, remains among the most disturbing and awakening travel experiences I’ve had to this day. As I watched little boys hard at work in utterly inhumane circumstances, with air so toxic that most men die by their early thirties and the work conditions so appalling that you wonder how these people can still smile, strong emotions were washing over me. And all this time, Efrain was next to me, cracking jokes and smiling.

There was a moment I strongly regretted going down into the mines. I knew about child labor in many parts of the world but did I really have to see it firsthand? And was I contributing to any change by paying a pitiful $20 for the half-day tour? What I felt was an immense separation between me – a tourist – and them – the miners.

I wondered if it was pure voyeurism on my part. The very same voyeurism that made me go to Havana’s worst slum, where even police doesn’t dare to enter. I tell myself I seek such experiences to be able to spread the message, to inform, to inspire to change… Or maybe I am just appeasing my conscience.

Last year, I watched The Devil’s Miner, an award-winning documentary about the 14 year-old Basilio Vargas and his 12 year-old brother Bernardino, both of whom worked in Cerro Rico. The flashbacks from my visit to the mine gave the film that personal edge – and gave me a serious kick.

The film was made several years after my descent into Cerro Rico. With the credits rolling, I wondered how I could simply walk away from what I saw in those mines. Telling the story to countless friends, strangers and acquaintances clearly wasn’t enough.

I think of Efrain a lot. I remember his smile and the way he called me gringita. I wonder what had happened to him. He’s over thirty now. I hope.

For more about The Devil’s Miner and how to help the children in the mines of Potosí, see www.thedevilsminer.com.