 Complete the following phrase:  The Mercedes-Benz Arena features a unique fabric roof construction, making it easily recognizable. Made of precision-tailored membranes of PVC-coated polyester, the roof tissue is durable enough to withstand 1,000 kg of weight per square decimeter. It is suspended from an aesthetic steel frame that runs around the entire stadium weighing approximately 2,700 metric tons. The steel cables connecting the roof to the frame alone weigh about 420 tons. The roof was added during the refurbishment preceding the 