Barcelona: Architecture in transition

Barcelona, not the capital of Spain but the capital of Catalonia, has long been shaped by a cultural and linguistic identity, with Catalan coexisting alongside Spanish in everyday life. Over the centuries, the city has developed into one of Europe’s most recognisable urban landscapes, where centuries-old buildings and architectural experiments exist side by side. The balance of preserving a densely built city with ancient facades, while leading an innovative scene of sustainable architecture, makes Barcelona a great example of architecture in transition.

Historical milestones shaping the city

La Sagrada Família, by architect Antoni Gaudí, is arguably the city’s most iconic landmark. At the beginning of the year, a white cross-construction was placed on top of the basilica, marking the completion of its central tower. La Sagrada Família now rises 172.5 metres above ground level, making it the tallest church in the world. The building has been under construction since 1882 and still remains unfinished to this day - however, the remarkably detailed structure is now one step closer to completion, 100 years after the death of Gaudí. Furthermore, the work of the famous Catalan architect can be admired all over the city. For instance in the Eixample district, where Casa Batlló catches the eye with façades of broken ceramic tiles. As well as the UNESCO World Heritage site, Park Güell, which houses fantastical sculptures and Gaudí's old residence.

Still, in more recent times, the urban landscape in Barcelona has been shaped by the Olympic Games hosted in 1992. The old factories in the Poblenou district were demolished to make way for The Games, leading to the creation of the Olympic Village and more than two miles of artificial beach with sand from Egypt. Overall, the preparations for the Olympics transformed the city for the better - and for the greener. Vast parks, such as the Parc del Litoral and Poblenou Park, were created, along with many sports complexes that were subsequently converted into parks and green hubs after the games. 

The revolution of the Superblocks

Another distinguished urban innovation first realized in Barcelona is the Superblock, locally called the superilles. The vision was an initiative from 1987 by the Spanish architect Salvador Rueda. The theory consists of 3 x 3 grids in a city block with limited use of cars, pedestrian-friendly zones and enhanced green areas. Today, this type of urban planning is an inspiration on a global scale and incorporated in cities such as Berlin, Vienna and Los Angeles.

Guim Costa is the current Dean of the Catalan Architect Association, as well as running his own studio, Costa Calsamiglia Architect. He has been involved in Superblock projects leading up to the formal realization in 2016, when the City Council first incorporated the initiative in the areas Poblenou and Sant Antoni.  

The concept of the superblocks today is not only environmentally sustainable in the sense of diminishing air pollution and creating green hubs; it also the social welfare for the citizens.

“I think that the Superblocks started with the acoustics, with the contamination, then it’s followed with the importance of social relations between elderly and young people,” Costa explains. 

The superblock theory is based on 53 indicators. The architect especially highlights solving the issue of urban mobility; this can be solved by the reduction of car use and by prioritizing pedestrian-friendly areas to enhance active transportation. Also by walking and cycling. The underlying advantage of being a densely populated city, with approximately 1.7 million residents and high rates of tourism, makes Barcelona very sustainable in a sense of potential proximity.

“In a 15-minute walk you have all the services around without having to take a car; cinemas, libraries, supermarkets, medical centres, schools,” Costa says.

He elaborates on the key idea of the Superblocks: “The idea is to have a very efficient public transport and that people go walking to school and work.” 

Bringing together communities

Xavier Costa Alos recently moved into the centre because of a new job, and is still settling in. Barcelona is not entirely new to him, since he already lived here during his studies. Today, he went to explore his new neighbourhood: the area of Sant Antoni. While crossing the streets of Comte Borrell, he encounters a Superblock in its full expression. He sits down on a bench with a cup of coffee, opens a book, and starts to read.

While he reads the first pages, cyclists cross the square, children play around with a ball, and elderly people watch the bustle from the shade of the trees. Costa Alos appreciates that he doesn’t necessarily have to spend money here - something that is not always the case in a highly touristic and consumption-driven city like Barcelona. Since none of his friends had time to meet today, he went out on his own. Places like this make him feel less alone, he says.

“Even if you're not lonely, to feel that you're part of a society might be very beneficial.” 

While enjoying the vibes of these public spaces, the 41-year-old also believes, that residents need alternatives, such as better public transport or better-developed cycling paths, if the city decides to restrict car traffic in areas like this. The topic of Superblocks is indeed a very controversial one. When the initiative was first implemented, many protested, partly because of the relocation of bus stops. In addition, residents feared that traffic congestions would increase significantly in the surrounding streets. 

According to the Barcelona City Council, the environmental benefits in the superblock of Sant Antoni are visible, with an overall decrease of 17% in daily vehicle traffic in the area from 2017 - 2022. The data also shows a significant 40% decrease from the toxic air pollution substance nitrogen dioxide, most commonly sourced from vehicle use. In three evaluated Superblocks residents and workers furthermore reported better wellbeing, greater tranquility and improved sleep quality, as well as more social interaction. 

Nature as a part of the equation 

The sustainable architecture in Barcelona takes many shapes and forms. One approach to look at the architecture practice in a different, yet more sustainable way, is practiced by the Director of the UIC Institute for Biodigital Architecture & Genetics, Alberto T. Estévez.

Estévez founded the Master Programme for Biodigital Architecture in 2000, and he was the first to apply genetics to architecture. The professor explains this niche of architecture very simply,

“You study nature, you study biology. It’s not that you make a flower as a building - you must look at the systems of the biological network and apply it to architecture.” Estévez says. 

He also underlines the concept of solar passive architecture in his own sustainable studies.

“I am the first architect of my generation to make houses solar passive. The idea of auto-sufficiency is the most sustainable way of thinking,” he continues:

“What does this mean? You take the resources, that you have in your surroundings - the water, air, sun and the soil.”

In this way, the buildings are self-sufficient.

The Biodigital Classroom in the building of UIC is plastered with posters of futuristic-looking buildings, 3D printed shapes and zoomed in photographs of animals and plants  - the inspiration for this type of architecture. The current master programme is coming to an end, and the students are working hard to finish their miniature buildings that are inspired by the United Nations Sustainable Development Goals (SDGs). Goal 11, "Make cities and human settlements inclusive, safe, resilient and sustainable", is especially a guideline for the students to think of more sustainable architecture.

The Sustainable Development Goals 

It is not unusual to involve the Sustainability Goals in the Master programme projects, Estévez explains. Last year the Biodigital Architecture Master student Konstantina Melachropoulou won the UIC's award on the Final Masters degree project (TFM) on human rights, sustainability and social action. Today the former student works as an architect in Greece after finishing her studies in 2025.

Her project "Wingy bones. A metaphysical journey to Biodigital Architecture" explores the themes of sustainability and the SDG 12 "Responsible consumption and production" and SDG 13 "Climate action".

“I tried to incorporate nature in the facade of my building. I took the idea of the ‘vertical garden’, that is seen all around Barcelona, to give space for nature to grow,” she explains.

Young architects, like Melachropoulou, but also experienced architects, like Costa, carry a big responsibility when it comes to urban building and planning; according to the latest UN Global Status Report for Buildings and Construction the building sector drives 34% of the global CO2-emissions. Buildings also consume 32% of the world's global energy. Furthermore, materials like cement and steel alone drive 18% of all building CO2-emissions, highlighting the urgent need for architects to shift away from these materials and think about new solutions.

Consequently, the former student believes that her generation is taught to take this into account in the biodigital studies. For instance, she talks about Antoni Gaudí as an important source of inspiration.

“Gaudí used the idea of bone in his buildings. I was trying to mimic the form of a bone,” she explains.

Gaudí plays a huge role in the research of making sustainable architecture with the biodigital idea of organic systems and structures. Professor Estévez believes that we in today's world, can learn a lot from the world-famous visionary architect, who widely used organic shapes in his structures. 

“Gaudí said, 'this tree is my teacher. Nature is the book where everything is written',” Estévez quotes.

The professor is currently curating an exhibition in Barcelona, Learning from Gaudí in the 21st century, which combines celebrating the work of the architect and marking his 100 year death anniversary. 

The UIA World Congress of Architects 2026

Barcelona has also been awarded the role of hosting the UIA World Congress of Architects and therefore named the UNESCO World Capital of Architecture 2026. Being the director of the congress, Guim Costa wanted to make this year special. It’s the second time since 1996 that Barcelona hosts this enormous event, with an international scene of architects and scientists. During five days, running from 28th of June to the 2nd of July, the itinerary of the conference will focus on the theme, "Becoming. Architectures for a planet in transition".

The theme elaborates into six different axis being; more-than-human, attuned, embodied, interdependent, hyper-conscious and circular. 

“Becoming means rehabilitation, means degeneration, the cycle of the building. Everything is related to time. The aims that we have are housing, sustainability, circularity, energy, efficiency, aesthetics and beauty. During these three days, we have morning and afternoon with each part of an axis,” Costa explains and elaborates on the importance and honour of hosting.

“I think Barcelona is one of the most architectural cities in the world, “ Costa states, “I already talked to the mayor of Barcelona that the legacy of this congress has to be something related to the biennale on ‘architecture thinking’ or ‘urban planning’.” 

However, despite the strong architectural image of the city, the government does not seem to push to integrate sustainable visions at the moment.

Related to, for instance, the Superblock initiative, Costa is enthusiastic but giving the process time “The politicians are not pushing for the Superblocks. I think the city is digesting a little bit, because it’s been controversial.” 

Touched upon before, Barcelona is not only a dense, but also a very completed and compact built city. Instead of building new, the architect believes in rehabilitation and reconstructing, with a focus on the circularity of the materials. 

“You also have to balance the virtues of sustainability and the virtues of heritage,” he mentions pointing at the old facades framing the streets.

“You have to be aware of what you are treating.”