The barrio at the top of Metrocable Line K, transformed from a no-go neighbourhood into a civic-pride symbol of the city's reinvention. The architect Giancarlo Mazzanti's Biblioteca España — three black-cubic library volumes perched on the ridge — was the first signal of the change, though structural failures forced its closure in 2014. Walk the streets immediately around the metro station; the views over the valley are extraordinary, the murals everywhere, and the food cheap and good.
Go with a local guide on a first visit; the area is much safer than it was, but is also not a tourist district.