Santiago Calatrava´s steel and glass Campo Volantin footbridge hasbecome as distinctive a part of the Bilbao skyline as the nearbyGuggenheim Museum.

Butin a spirited defence of his artistic integrity, the Spanish architectis suing the city of Bilbao for €3m (£2m) for violation of copyright,for allowing an extension to the bridge to be built by another stararchitect.

The Japanese architect Arata Isozaki designed an extension to the10-year-old footbridge to connect with his recently completed riversidehousing development nearby. The court case has prompted a heated debateover whether a public building can be deemed a work of art.