Barcelona's Provincial Council, known as the Diputació, has a valuable architectural heritage comprising two outstanding Modernista buildings. The first is the Palau Güell, the residence designed by Gaudí and built between 1886 and 1888 for Eusebi Güell, who would later become his patron. It is an early work by Gaudí in which you can already find the features that will come to characterise his later work, such as original building solutions and an insistence in taking into consideration the symbolic features of a building. The Diputació has owned the building since 1945. During the last few years, work has been carried out to return the building back to its former sumptuous glory, when the Güell family resided there.

The Casa Serra, on the other hand, was designed by Puig i Cadafalch as a residential palace (1903-1908) in a style that recalls the aesthetics of Noucentisme. It housed a religious school after the Civil War and was transformed into the main offices of the Diputació in 1987, following a daring design intervention by Federico Correa and Alfons Milà.