When it opened in 1974, the Westfalenstadion set a new standard. But 20 years later, it was no longer competitive in terms of the comfort it offered. The stadium was rebuilt in several phases between 1995 and 2003, resulting in a venue that kept its character and became a landmark for the city of Dortmund. Since then, SIGNAL IDUNA PARK has been the only stadium in Germany with a capacity of more than 80,000.

First expansion phase in 1995: Upper tiers containing 6,000 seats each were added to the West and East Stands. The West Stand has since been home to the VIP stand; a VIP area has also been set up there.

Second expansion phase in 1999: The capacity was increased to 68,600. The South Stand, the epicentre of Dortmund's football enthusiasm, was increased to 24,454 places, making it Europe's largest standing-only tribune.

Third expansion phase in 2003: The works finished with the closure and the expansion of the corner areas. The corner pylons, which supported the roof inside the stadium, were replaced by the eight 62-metre-high yellow steel pylons installed on the exterior which have since become an integral element of Dortmund's skyline.