As part of Medellin's urban renewal, community centres have been built and schools have been renovated. Narrow alleys have been cleared to make way for a green belt, which includes parks, playgrounds, gardens and a walkway providing spectacular views of the city and mountains.
Without the escalator and cable car, which provide access for builders, workers and teachers, this would not have been possible.
As we sat with residents in a local café, we could see they were proud that the comunas have become a magnet for tourists. They're also a model for successful urban change, which attracts city planners like us from all over the world.
Not everything in perfect, though; crime rates are down, but levels of poverty and unemployment are still high, and violence still exists. "Sure, there are many problems that we must solve, but I wouldn't want to live anywhere else," says Maria. This trip made us realise the importance of urban planning. If done wisely, it can really make a significant difference to people's lives.