Concrete may not be the most glamorous of materials, and is not usually thought of as a big draw for tourists, but it is doing for Valencia what titanium has done for Bilbao.

The City of Arts & Sciences is a startling string of structures which has transformed a neglected part of Valencia between the centre and the sea. The elegant scheme was designed by Santiago Calatrava, who was born in the city and has clearly thrown his heart and soul into this astoundingly ambitious project, which is a 21st-century version of the great medieval cathedrals.

Architecture that looks spectacular in photographs can be a bit of a disappointment in reality, but every time I go to Valencia I just stand there, gawping slack-jawed at the structures sparkling in the sunshine, looking more like sculptures than buildings.

I have been observing the development of the City of Arts and Sciences for more than a decade now. Every time I go to Valencia another bit has been added on.

The first section was the planetarium, called the Hemisferic. The structure is like a human eye, with the auditorium in the eyeball. Visible as a semicircle by day, at night it is reflected in the surrounding white mosaic pool to form a perfect sphere.

Next to is the Principe Felipe Science Museum, a lopsided pavilion that seems to be just light and air, held up by a zigzagging mesh of tautly-strung white ribbons. It looks like the skeleton of a dainty prehistoric monster.

It is clear that Calatrava was inspired by Gaudi, as chevrons, parabolic arches and fragmented tiles feature throughout the complex, which also includes an opera house and an aquarium, the latter designed by Felix Candela.

The opera house, the Palau de les Arts, is contained within a diamond-shaped frame, with a curving spine arching over the top of the structure like a gigantic fish bone. It is hard to believe that concrete can look so soft and light, but that is the genius of Calatrava.