Barcelona is located on the Mediterranean coast, confined by the sea, the Serralada Litoral mountain range and the Llobregat and Besòs deltas.

The urban structure of Barcelona responds to four stages of its development. Firstly, the primitive nucleus, called Barcino, surrounded by the Roman walls, still visible in the Gothic Quarter. Secondly, the medieval walled enclosure, which lasted until the demolition of the walls in 1854. A third sector of the city is the Eixample of Barcelona, built according to the Cerdà plan of 1859 outside the walls, which introduced innovative principles of hygiene and equality. Finally, the metropolitan plan of 1976 promoted a more fluid connection between the different urban fabrics, regenerating post-industrial spaces and opening the city to the waterfront.

Between the end of the 20th century and the beginning of the 21st, the city of Barcelona stood out as an attractive tourist destination, home to world-scale events and a leading example for urban transformation.