The beginnings of the area known as Eixample were the Barcelona plains outside the city walls, between the city and surrounding towns.

Like many European cities, the city of Barcelona is not detached from recently created industries and demographic expansion. However, the walls, the political situation and the fact that all the land outside the walls was considered as a military area, prevented them from being able to install new industries in surrounding areas. There was a ban on construction within this huge open space, and it was for exclusive farming use by the peasants of Barcelona and nearby towns and villages.

The streets of Eixample are generally 20 metres wide, of which 10 metres in the centre of each street is used as roadway and 5 metres either side are for pavements. However, due to various requirements, certain streets were designed to be much wider. This was done without affecting the regular pattern of 133.3m blocks, by reducing the size of the blocks by an appropriate amount. Such streets include Gran Vía de las Cortes Catalanas, under which run the Metro and mainline trains; Calle Aragón, along which the railway ran in open air for many years until it was eventually put underground; Calle Urgel and others.