Cities are built in public spaces

• Opinion piece, published in La Vanguardia on May 29, 2026

For many years, we have understood urban infrastructure as the collection of elements that enable a city to function: roads, power grids, transport systems. These are undoubtedly essential. Yet there is another form of infrastructure that is just as critical, although often less visible: public space.

Streets, squares, parks and promenades are not merely urban settings; they are the social infrastructure that sustains community life. They are where people meet, businesses thrive, culture unfolds and social interaction takes place. Ultimately, they are where a city truly becomes a community.

At a time when the world is becoming increasingly urban, the value of these spaces is greater than ever. According to the United Nations, more than 55% of the world’s population now lives in cities, and that figure is expected to approach 70% by 2050. In this context, the quality of urban life will depend to a large extent on how we design and care for the spaces we share.

Barcelona is a particularly meaningful example of the relationship between cities and public space. From the Eixample plan designed by Ildefons Cerdà in the nineteenth century to the urban transformations of recent decades, the city has shown that urban planning is not merely a functional or aesthetic exercise but a powerful tool for improving people’s lives. It is no coincidence that Barcelona has been named UNESCO World Capital of Architecture 2026. This distinction aims to place architecture at the centre of the debate on major contemporary urban challenges, including city growth, climate transition and the need to create healthier and more inclusive environments. In all of these challenges, public space plays a fundamental role.

Twenty-first century cities need spaces capable of fulfilling multiple functions simultaneously: supporting sustainable mobility, mitigating the effects of climate change, stimulating economic activity and encouraging social interaction. It is increasingly clear, for example, that green areas and open spaces contribute significantly to both physical and mental well-being. The World Health Organization has highlighted the direct relationship between access to quality urban spaces and higher levels of well-being and physical activity. At the same time, these spaces can function as climate infrastructure, helping to reduce the urban heat island effect and improving water management during periods of intense rainfall. Yet for public space to fulfil all these roles, good design alone is not enough. It must also be built well.

The quality, durability and sustainability of the materials used to construct streets, squares and urban facilities are essential if these spaces are to stand the test of time and adapt to emerging environmental challenges. In this regard, the transformation of the construction sector has become a key element in shaping the future of our cities. The built environment accounts for a significant share of global environmental impact, making it imperative to advance towards construction solutions that are more efficient, longer-lasting and aligned with the principles of the circular economy.

This means driving innovation in materials, optimising production processes and embracing solutions that combine technology, design and sustainability. Industrialisation and technical expertise now make it possible to develop more resilient, adaptable and durable solutions capable of supporting the long-term evolution of our cities.

But city-building is, above all, a collective endeavour. Architects, engineers, public administrations and industrial companies must work together to address challenges that are becoming increasingly complex. Cities have always been the result of collaboration between creativity and technical capability, and today that partnership is more important than ever.

Throughout its history, Barcelona has demonstrated that urban planning can be a powerful instrument for social transformation. From its squares and markets to its avenues and waterfront promenades, the city has built an identity rooted in the quality of its shared spaces.

At a time when cities around the world are searching for more sustainable, inclusive and resilient urban models, this legacy is particularly relevant. Because, ultimately, beyond buildings and infrastructure, what defines a city is the quality of the spaces where everyday life unfolds. And those spaces, though they often go unnoticed, are probably the most important infrastructure of all.