When I was growing up in Lima in the 1970s, Western visitors were astonished by the shantytowns, the barriadas, as they were known, that ringed that grimy city. Why, they asked, did people leave the countryside to live in these squalid slums? Why swap the pure air of the Andes for traffic fumes and sewage?

It was a very First World question. No Peruvian ever asked why people were quitting villages that lacked electricity and clean water. The barriadas may have been ugly, but they were humming with enterprise. They offered work, access to schools and clinics, a power supply. They were, for most of their denizens, transitional, a staging post between mountain squalor and something better.