Olympic stadia are always among the world's architectural milestones; because the stadium itself imposes functionally necessary constraints on the architect's imagination, however, the special and distinguishing factor is in many cases the roof structure. This, indeed, was also the case with the arena constructed for the XXVIIIth Summer Olympics, held in Athens in 2004, the creation of which was entrusted to star Spanish architect Santiago Calatravas. The two halves of the stadium's roof together contain a total of 17,000 tonnes of steel and glass, but nonetheless appear to be defying gravity.

The 6,150 tonnes of steel for the project originated from Dillinger Hütte GTS, and with good reason - the fact that the renowned German platemakers could supply the heavy plate in widths of up to 5 meters made it possible to dispense with a large number of costly longitudinal welds in plate thicknesses of up to 100 millimeter. This enabled plates to be bent to form half-shells, of which two in each case were welded together to form a tubular segment. This unusual installation procedure - the halves of the roof were fabricated separately outside the stadium and then hoisted into their final position after completion - was the factor which made it possible to meet the extremely tight completion schedule.