Built for the 1998 Lisbon World Exposition, the building was designed by Álvaro Siza Vieira to be the thematic centerpiece of the festival and the host country’s national pavilion.
The theme of the Expo, "The Oceans: A Heritage for the Future,” commemorated the heritage of Portuguese discovery and demanded from the architect a sensitive interplay between the pavilion and the harbor. Siza, who at the time was Portugal's most renowned modern architect, was selected to design the building as the grand entrance to the fairgrounds.
With the help of fellow countryman Eduardo Souto de Moura and the engineering expertise of Cecil Balmond, Siza created a space that was visually striking and highly effective at meeting the festival’s programmatic needs and site-specific requirements.
Siza chose to split the building into two parts: one portion was designed to be adapted for various uses, while the other would be an outdoor yard, where he would create a strong architectural gesture. The architect covered the patio with a 70-metre-long concrete canopy that bends down in the middle, and frames views to the Tagus River.
"I could not use form in a free way, because I did not know what was going to be decided, [...] The result in my opinion is interesting because it's a very special half and a very almost banal second building side-by-side." — Álvaro Siza Vieira
The 20-centimetre-thick canopy curves up at each end to rest on two large porches with the slabs stopping short at the end to reveal the cables inside. Each of the large porches flanking the canopy comprises nine columns that are covered in ceramic tiles and spaced apart to allow create shadowy nooks in between. These structures form porticos into the patio and then into the adjoining building. Monolithic volumes are arranged around central courtyard and rendered white or covered in pale tiles to match the tones of the canopy.