‘Radical Cities: Across Latin America in Search of a New Architecture’, by Justin McGuirk

Radical Cities: Across Latin America in Search of a New Architecture, by Justin McGuirk, Verso, RRP£17.99/$29.95, 288 pages

From a distance, the favelas creeping up Rio de Janeiro’s hillsides can resemble picturesque Tuscan towns. Up close they look rather different, vivid symbols of the inequality and social discord that animated protests in the run-up to the World Cup in Brazil and which continue to define the country’s image alongside the officially approved trio of samba, sunshine and beautiful football. Feared by the authorities as hotbeds of crime, sometimes coveted by the wealthy for their prime city-centre sites, such informal settlements are an inescapable part of life in the world’s most urbanised continent. They are also home to some of the most interesting architecture taking place anywhere in the world.

More than 80 per cent of Latin America’s population lives in cities, making the region a kind of testing ground for the effects of explosive global urbanisation. In his fine and timely book Radical Cities, the British writer and curator Justin McGuirk takes a road trip to seek out not only the problems caused by rapid growth but also the most radical and influential ideas to have emerged in response over the past couple of decades.

Take the Chilean architect Alejandro Aravena, who, when faced with the challenge of designing ultra-low-budget accommodation for the poor, decided to build only half a house. The infrastructure and frame are there but it is up to the inhabitants to expand the building as their family grows. The result is an attractively ad hoc streetscape of colourful DIY architecture that points to one possible future and intriguingly avoids the pitfalls of the giant modernist housing schemes, criticised for imposing an alien pattern of living and disengaging the inhabitants.

Most interesting of all are the Colombian stories from Bogotá and Medellín. McGuirk introduces us to Antanas Mockus, the brilliant philosopher-clown who, as mayor of Bogotá, used to dress up as the caped superhero “Super Citizen”. Mockus made his name with a series of headline-catching stunts including replacing traffic cops with mime artists and distributing red cards to drivers so they could admonish each other for violations, soccer-style (Bogotá’s traffic fatalities dropped by more than 50 per cent). Without big investment in urban infrastructure, Mockus transformed citizens’ attitude to the city and their engagement with it, giving them back a sense of control.

Mockus’s legacy is contested, as many of his stunts have failed to bear long-term fruit. More transformative are the changes in Medellín. The murder capital of the world in the early 1990s, Colombia’s second city has gone through an astonishing turnround and, apart from radically reduced crime, the most visible manifestation of this is a kind of architectural renaissance. The surgical interventions into the informal settlements that crawl up the hillsides surrounding the city have attracted international acclaim.

If the solution to slums was once to demolish them and build huge housing estates, Medellín instead recognised the value inherent in the existing social structures. Instead of driving roads through the settlements, the city authorities built a cable car and escalators, brilliantly adapting machines associated with skiing or shopping to transport people up the steep hillsides, and drastically cutting commuting times.

Then we are taken to the Torre David in Caracas, the carcass of an unfinished skyscraper now appropriated by squatters who have built an extraordinary co-operative society inside. Finally there is Teddy Cruz, an architect working on the margins of San Diego and Tijuana on the US-Mexico border, each dependent on the other for labour or employment yet so radically different. How, Cruz asks, can cities adapt and share in the proceeds of the wealth they create between them?

These innovations might seem marginal but the global explosion in urban populations will be accommodated largely in informal settlements. So far, no city has managed to solve the problems associated with them through new housing – the scale becomes overwhelming. So the answer must be to accept their existence and look for ways of improving conditions. None of the ideas outlined in Radical Cities solve all the problems but together they present an intriguing picture of an activist urbanism and architecture that has made a real difference.

Perhaps the question is not only how the slums can be improved but how the established global cities, with their massive immigration, rising inequality, retreating states and moribund architecture, might be able to learn from the radical solutions emerging from the margins.

Edwin Heathcote is the FT’s architecture critic