Subsequently, urban development was marked by the increase in population due to immigration from other parts of Spain, which led to various urban projects such as the Regional Plan of 1953 or the Metropolitan General Plan of 1976. Another significant increase in the area of the Catalan capital was the annexation of several municipalities adjoining Barcelona between the late nineteenth and early twentieth centuries, which led to a Plan of Connections ( Spanish: Plan de Enlaces) drawn up in 1903.

The situation changed with the demolition of the walls and the donation to the city of the fortress of the Citadel, which led to the expansion of the city across the adjacent plain, a fact that was reflected in the Eixample project drawn up by Ildefons Cerdà, which was the largest territorial expansion of Barcelona.

Until the nineteenth century the city was constrained by its medieval walls as it was considered a military square, so its growth was limited.

The urban evolution of Barcelona has been constant since its foundation in Roman times to the present day, although since the nineteenth century it has been accentuated thanks to the Eixample plan and the aggregation of neighboring municipalities. The urban planning of Barcelona developed in accordance with the historical and territorial changes of the city, and in line with other defining factors of public space, such as architecture, urban infrastructure and the adaptation and maintenance of natural spaces, parks and gardens.

Forge of empire city planner