The centre-point of the Paralympic Games - and the beating heart of the whole of London 2012 - is the imperious 80,000-capacity Olympic Stadium, billed as the most sustainable major sports arena ever built, which will host all Paralympic Athletics events as well as the opening (29th August) and closing (9th September) ceremonies. Located in the south of the Olympic Park and made from a quarter of the steel used to build its equivalent for Beijing 2008, the £537m Olympic Stadium also features low-carbon concrete made from industrial waste, while the top ring was built using surplus gas pipes. In short, although perhaps not as visually appealing as the "Bird's Nest" in Beijing, the whole vast structure is testament to London 2012's sustainability and environmental aspirations. During the Games, there will be 25,000 permanent seats in the lower tier, and a temporary lightweight steel and concrete upper tier will boast a further 55,000 seats. Spectators reach the "island" site from five bridges that cross the stadium's surrounding waterways, which at night time will reflect the 14 triangular stanchions of floodlights that shine down upon the interior. Once complete, the stadium's top layer will be covered by a stretched sustainable material - not only to make the whole thing easier on the eye, but also to act as shelter for two-thirds of the spectators. Facilities inside the stadium include 700 rooms (medical support facilities, changing rooms and toilets) and an 80m warm-up track. Taking inspiration from the outdoor fan zones of the 2006 World Cup in Germany, all stadium services - such as refreshment and merchandise outlets - are located on the outside of the venue on a 'podium' that will surround the stadium and add to the Park's festival feel.