Why now? Because the city has become the home of one of the most spectacular and daring modern buildings built this century. Housing a fascinating collection of 20th century art, the Bilbao Guggenheim Museum is set to become one of those landmarks which, like the Sydney Opera House,symbolises its city.

A vast titanium-clad, symmetry-free construction, it sits by the River Nervion, partially tucked under a bridge from where you get one of the best views. Its sinuous shapes gleam in the sunshine.

It came into being as the result of a happy convergence of needs. ln the early 1990s the Bilbao authorities wanted a centrepiece for a Pounds 1 billion regeneration scheme, which included a new underground railway (with entrances designed by British architect Sir Norman Foster), a river bridge, a concert hall and, still to be built, a library and science museum.

At the same time, the New York-based Guggenheim Museum was becoming increasingly dissatisfied with the fact that only 80 per cent of its vast collection could be displayed at any one time. The rest was stored in vaults because of lack of appropriate buildings to show them.

So, Bilbao built the museum and Guggenheim supplied the ex-hibits, many of which will be shown on rotation to provide changing displays. There will also be a permanent collection, which the city authorities will build up with a starting fund of around Pounds 20 million. This will contain many works by Basque and Spanish artists and serve to make the museum feel less like an alien cultural implantation.

The architect of this extraordinary building is the American Frank Gehry,whose lifelong, self-admitted obsession with fish and snakes is reflected in the exterior’s silvery titanium “scales” and serpentine form. He also draws on Bilbao’s industrial and maritime past for inspiration, with shapes reminiscent of ships and steel works.

Inside, rooms of many dimensions - the largest is the size of an aircraft hangar - fan off from a vast central atrium which soars, cathedral-like, to the full height of the building.

Many of the spaces are connected by walkways which overlook galleries below (this is not a building for vertigo sufferers) and provide the best views of some of the sculptures and paintings.

It is a surprisingly light and airy building - the use of glass is much more obvious from the inside than outside - and always stimulating. Gehry shuns straight lines. Even the lift is disguised within a glass structure.

It is a building designed for the huge artworks of the 20th century. Works include walk-through sculptures, outsized paintings and video installations. Some have been specially commissioned for particular sites, for example, a series by Francesco Clemente and an electronic installation by Jenny Holzer which reaches up to the ceiling in the central hall.

The contents will be regularly changed, but on the strength of an exhibition earlier this year, fears that the museum would be given only leftovers from the New York Guggenheim Museum are groundless.

The museum works its way through European masterpieces from the first decades of the 20th century, through mid-century developments in European and American art, including works by Clyfford Still and Willem de Kooning and, later, Andy Warhol, Carl Andre and Roy Lichtenstein, to contemporary works, including examples by British artists Richard Long, Gilbert and George and Damien Hirst. Along the way you can also see work on paper by Alberto Giacometti and paintings by Georg Baselitz and Julian Schnabel. Younger Basque and Spanish artists are represented too.

Pre-museum Bilbao might not have been an obvious tourist destination but that doesn’t mean there are no other places of interest to visit. It would be a pity to miss the beautiful old town with its narrow, busy streets and cafe-encircled square. And the Museo de Bellas Arte is not entirely eclipsed by the Guggenheim. As well as 12th to 18th-century Spanish works, it has some interesting modern paintings.

If you are able to drive out of the city, a journey of about one-and-a-half hours will take you to the very pretty, but touristy, Cantabrian village of Santilliana, with its cobbled streets, 15th-century mansions and medieval church and cloister. It has been described by many, including Jean Paul Sartres, as the prettiest village in Spain.

It all contributes to making Bilbao a destination which would keep even the most energetic and avid tourist occupied for several days. As many school parties will undoubtedly be discovering, this is a part of Spain which can no longer be ignored.

A VISITOR’S GUIDE TO THE GUGGENHEIM

* The museum is open Tuesdays-Sundays, 11am-8pm. Schools can make a reservation for a tour in English through the Visitor Services Department.

* Teachers who want to lead their own party, should apply for accreditation to the Visitor Services Department. (This is to control the number of guides who are in the museum at any given time.) * Schoolchildren aged 12 and under on non-guided tours are free. For students aged over 12 the price is 350 pesetas (about Pounds 1.50) each, teachers free.

* Prices for guided tours depend on the number and age of the pupils (contact the Education Department).

* Information packages are available in English. Workshops are also available for younger children.

* Catering facilities within the museum are limited, so make arrangements to eat elsewhere.

* Address: Guggenheim Bilbao Museo, Adandoibarra etorbidea, 2-48001 Bilbao. Tel: general information: 34 4 435 90 80; visitor services: 34 4 435 90 90; education: 34 4 435 90 67.