Botta chose simple, essential lines enclosed in three elements: a base and 2 buildings, one parallelepiped in form and the other in the shape of an upside-down cone. A sort of crenellation at the top of the parallelepiped alludes to the ancient palaces and medieval fortresses that once stood on the tops of the hills.
The adjacent building suggests greater dynamism, with the slight slope of its walls seeming to rise upwards from the base or, to the contrary, collapse inside. The two buildings, which have in common a great simplicity, interact in different ways with the space around them and give the museum complex different connotations.
The particular layout of the stairwell permits it to be illuminated by natural light through a big skylight, and tapers down into the basement of the building, where visitors can proceed on to the contemporary art museum or the temporary exhibition area.