How the violent barrios of Medellin were transformed

A huge civic project has transformed the violent neighbourhoods of Colombia's second city
Medellin used to be one of the world's most dangerous cities, with a sprawling network of slums and a serious crime problem fueled by drug trafficking. During the 1990s, there was a dramatic transformation. A leading architect involved in the project, Carlos Alberto Montoya Correa, describes how the regeneration took place. 

Photo: Medellin viewed from a cable car Credit: Getty Images