Not to miss

La Pedrera

This hallucinatory, undulating beast is yet another madcap Gaudí masterpiece, built between 1905 and 1910 as a combined apartment and office block. Formerly called the Casa Milà, it's better known as La Pedrera (the quarry) because of its uneven grey stone facade that creates a wave effect, which is further emphasized by elaborate wrought-iron balconies.

Visitors can tour the building and go up to the roof, where giant multicoloured chimney pots jut up like medieval knights. On summer weekend nights, the roof is eerily lit and open for spectacular views of Barcelona. One floor below the roof is a modest museum dedicated to Gaudí's work.

Palau Güell

Closed for renovation until 2007. Gaudí's first work appears less flamboyant than his later efforts, but a journey to the rooftop reveals an amazing display of chimneys and mosaics. From here you can peer down into the studio at No 6 where Picasso, who loathed Gaudí's work, began his Blue Period.

Just a hop and a skip from La Rambla, this mansion is one of the few Modernista buildings in the Ciutat Vella. It was built in the late 1880s for Gaudí's patron, Eusebi Güell.

The compulsory guided tour starts grimly, in the subterranean stables where police tortured political prisoners after the Civil War. Dark grey marble stairs lead to a series of 1st-floor vestibules with columned galleries overhanging the street, designed to maximise space and natural light. The next floor contains the building's most sumptuous room, where the family used to entertain undaunted by the mammoth domed ceiling reaching three stories above them. Carry on up to the roof for a uniquely Gaudí-style flight of fancy.

Museu Picasso

Barcelona's most visited museum shows numerous works tracing the artist's early years and is especially strong on his Blue Period, with canvasses like The Defenceless, as well as ceramics and early works from the 1890s. The rest of the museum traces Picasso's life and travels.

The stunning stone mansions that house the museum are situated on the Carrer de Montcada, which was, in medieval times, an approach to the port. The 1st floor is devoted to Picasso's Blue Period. The 2nd floor displays his impressionist-influenced works, produced in Barcelona and Paris between 1900 and 1904. The haunting Portrait of Señora Canals (1905), from his Rose Period, is also on display. Among the later works, all painted in Cannes in 1957, is a complex technical series entitled Las Meninas, which consists mostly of studies on Diego Velázquez's eponymous masterpiece.