Millennium Dome air vents. View of specially designed air vents in the Millennium Dome,London,England,for an Underground train line running beneath the Dome. This,the largest dome in the world,will contain the Millennium Experience,a huge exhibition to celebrate the year 2000. The 2 mm thick roof,made of teflon- coated glass fibre fabric,is supported by 70 km of steel cables attached to twelve 100 metre high masts. Rainwater falling onto the roof will be collected,filtered and stored for use in the Dome's toilets. The Dome is 320 metres across and will be able to hold over 40,000 visitors. The structure has a lifespan of over 25 years |