26、The 2008 Olympic Stadium in Beijing is another design that makes us think about nature. Seen from the top, it looks as if the stadium is covered by a gray net of steel, and it looks just like a bird’s nest made of tree branches. Birds fill up the spaces between the branches of their nests with soft materials. Just so, the spaces in the structure of the stadium are filled with huge plastic bags full of air. Although the stadium is made of concrete and steel, the flowing lines and round shapes make the building look warm and friendly.