Accustomed to living with an illness that afflicts her lungs, the 5-year-old girl speaks in a low, gravelly voice that almost sounds adult: “We came to Chile for my surgery and work.”

The young girl and her family are among the tens of thousands of Latin American migrants and asylum seekers who have braved the highland plateau, with its extreme temperatures, for a new life in Chile. In recent years, the country has become a major hub for migration — and an alternative to destinations like the United States.

But the journey is difficult, and the Chilean government has ramped up efforts to close its borders to undocumented arrivals. Still, for refugees and migrants like Allyson, who hails from Bolivar, Venezuela, the voyage can spell the difference between life and death.

“In the hospital, we were told to leave because in Venezuela they couldn’t cure me if I got sick again,” she explains, panting as the trail takes her across one of the world’s highest borders, more than 4,000 metres above sea level.