Cable cars reaching the city’s margins, green corridors designed to cool the streets: Medellín is full of ideas for improving urban life. But how transformative have the much-praised projects actually been?

David Amen is a Brazilian graffiti artist, video maker and an art and media educator. Two of his artworks are featured in the D+C February issue.

The residents of Nigeria’s largest city suffer from severe air pollution, traffic congestion and car-centric urban planning. Local initiatives are proposing solutions to redesign public spaces and transport – from citizen science to car-free days.