The National Stadium (Bird"s nest) - Situated at the Olympic Green, it has a floor space of 258,000 sq meters. The National Stadium in Beijing is the main stadium for the 2008 Olympic Games. It is often dubbed the "bird"s nest" because of its featuring grid formation. The twig-like structure and the bowl-shaped roof are the masterpiece of the project. It is designed by Herzog and DeMeuron. The most unique feature of the structure is its "cushion" system which can fill the spaces within the building"s facade to regulate wind, weather, and sunlight. It can accommodate 91,000 visitors and hosted the opening and closing ceremonies, the track and field competitions and the football finals during the 2008 Olympic Games.