In 1841 the Barcelona City Council organised a design competition for expanding the city beyond its ancient walls. In 1860 the central government, after studying many different proposals, approved the plan by the engineer and urban planner Ildefons Cerdà, to develop the city according to a grid structure, forming the district which is nowadays known as l’Eixample (Catalan for The Expansion). The plan took almost a century to complete.
The most noteworthy formal solution of the plan was the incorporation of the block. Its vital shape, which is absolutely unique in comparison to any other European city, is distinguished by its square structure, with sides measuring 113.33 metres and chamfered corners at 45º.
The original plan established a maximum building height of 16 meters, and attributed a key role to parks and gardens within the blocks. Subsequent speculation altered the original design greatly. The plane tree was also chosen as the ideal species for planting in the city, with a gap of 8 metres between each tree.
Casa Batlló is located in Passeig de Gràcia, the main thoroughfare of the district of Eixample, in the very heart of Barcelona.