Frank Gehry's spectacular twisting titanium-clad modern art museum is perhaps the most celebrated building of the 1990s, even starting what would be called the 'Bilbao-effect': The idea in urban planning that a star-quality building can single-handedly change the entire image of a city. Although this effect is unproven in its pure form, the Guggenheim nevertheless changed the world wide perception of Bilbao. The graceful, sensuous curves, evocative of the ships that used to be ubiquitous along the docks of Bilbao, are covered in titanium squares, which resemble the scales of a fish and shimmer in the sunlight. In keeping with the maritime theme, appropriate for the setting, the skylights of the largest gallery (formerly known as the Fish gallery) are designed to look like the fins of fish. Many parts of the building are purely decorative, and don't serve any purpose. The permanent collection is not particularly impressive, but the museum always hosts at least one interesting temporary exhibit, frequently comprised of masterpieces from the other Guggenheim collections.