With the permission of the Guggenheim Museum, the metro is the other great icon that a contemporary architect has left in Bilbao. While Frank O. Gehry often created spectacular buildings, Norman Foster adheres strictly to function. Almost forty years after the inauguration of the metro, Foster's new work in the city, the expansion of the Bilbao Fine Arts Museum, which opens its doors this Monday, is once again a lesson in silent architecture. And yet, Foster's intervention –designed together with Luis Maria Uriarte– has emblematic elements, such as a spectacular open-plan temporary exhibition hall of 1,300 m²², which leads to about 700 m²² of terraces. Another is the old courtyard converted into a large atrium where sculptures by Eduardo Chillida and Richard Serra can be seen, all of them around the monumental fountain that Francisco Durrio made for the composer Juan Crisóstomo de Arriaga, who died prematurely at 19 years old. Until now this sculpture was outside, and with the new location it has recovered its character as a sound monument: the noise of the water evokes the weeping of the sculpture of the muse Euterpe that crowns it. "The ducts and pipes of the great hall are hidden to achieve a pure space to make the works of art shine," said Norman Foster this morning. "When Foster and Uriarte won the competition and Foster came to explain the project, they told us that we had asked for a good exhibition hall and that they would give us the most beautiful hall of any European museum," explains the museum's director, Miguel Zugaza, who wanted to close the tour with a room dedicated to Jorge Oteiza, the only monographic one, which has the air of a sanctuary.