A characteristic feature of the Opera building is the gigantic roof covering the entire building stretching all the way to the harbour front. Measuring 158 metres x 90 metres, the Opera roof is one of the largest roof constructions in the world. The innovative design of the roof, which Ramboll has projected in cooperation with Henning Larsen Architects, was the reason for the Opera winning "The 2008 IABSE Outstanding Structure Award". The Committee that selected the Opera as the winner complimented the design of the roof and the use of bridge construction principles. These principles provide strength, stability and stiffness to the 43-metre-long roof all the way from the columns of the foyer to the furthest corner of the roof.