Barcelona, part 2: the Eixample grid and the geography of breathable streets

From the air, Barcelona’s Eixample looks almost impossibly calm: a pale grid pressed between the old city, the hills and the sea. Its order is not the cold order of a spreadsheet. It is a nineteenth-century public-health project drawn at urban scale, a plan that tried to give a growing industrial city what cramped streets could not: daylight, air, movement and room for daily life.


The key figure was Ildefons Cerdà, an engineer, planner and social reformer. In the 1850s Barcelona was still shaped by military walls that had long prevented expansion. Those walls began to come down in 1854, just as population, industry and railways were making the old city dangerously dense. Cerdà studied how people moved, where disease spread, how much space workers had at home and how streets functioned as shared infrastructure. His enlargement plan, approved in 1859, was not simply a drawing of new blocks. It was an argument that urban form could improve health.

The Eixample’s most famous feature is the block with cut-off corners. Instead of sharp rectangles, Cerdà used octagonal islands created by chamfers, or xamfrans. A typical block is about 113 metres on each side, and the streets were planned generously, often around 20 metres wide. The chamfered corners made turning easier for vehicles, improved sightlines and created small moments of openness at intersections. Long before private cars dominated Barcelona, the grid was already thinking about mobility.

Cerdà imagined more than traffic. His ideal blocks were not supposed to become solid masses. Buildings would leave space for gardens, sunlight and ventilation; services would be distributed evenly; social classes would not be segregated into distant quarters. The plan was rational, but its ambition was humane. It treated air almost as a civic right.


Reality negotiated hard. Land values rose. Courtyards were built over. Many blocks filled in and climbed higher than Cerdà intended. The Eixample became elegant, productive and dense, but less green than the reformer had hoped. Today the district covers about 7.48 square kilometres and has one of Barcelona’s highest population densities, above 35,000 inhabitants per square kilometre. That number explains both its vitality and its pressure. Shops, schools, clinics, apartments and cafés sit close together; so do noise, heat and traffic.

This is why the Eixample remains so interesting. It is not a frozen masterpiece. It is a living machine that keeps being adjusted. The same grid that once promised hygiene now gives Barcelona a framework for climate adaptation and calmer streets. Because the blocks are regular and connected, the city can test changes at the scale of a neighbourhood instead of only one avenue at a time.

The best-known recent tool is the superblock, or superilla. The idea is simple: group several ordinary blocks, often a three-by-three set, and move through traffic to the perimeter, while the interior streets become slower, greener and more welcoming to walking, cycling, play and local access. Barcelona’s pilots, including Poblenou and Sant Antoni, turned junctions and lanes once used mainly by cars into plazas, benches, trees, bicycle routes and space for neighbours.

Measured facts matter because urban optimism should be honest. Superblock projects have been studied for reductions in motor traffic, noise and air pollution inside transformed areas, while critics have raised concerns about displaced traffic, deliveries and uneven benefits. Those tensions are real. But the experiments show a powerful lesson: street design is a public-health instrument, just as Cerdà believed. A kerb, a tree pit, a bus lane or a playground can change how bodies breathe and how neighbours meet.

The Eixample also teaches that geometry alone is not enough. A grid can support equality, or it can support speculation. Wide streets can carry light, or they can carry too many cars. Courtyards can be gardens, or they can vanish under profitable floor area. Cerdà’s great gift was not perfection. It was a generous urban grammar, one Barcelona is still learning to speak more quietly, more cleanly and with more room to breathe.