Bird's Nest (Beijing National Stadium)

The steel lattice icon of the 2008 Olympics/Stadiums

Designed by Herzog & de Meuron and artist Ai Weiwei, the Beijing National Stadium earned its 'Bird's Nest' nickname from the interwoven steel beams that form its exterior. Built for the 2008 Summer Olympics, it used 42,000 tonnes of steel in a structure that looks like a giant picked up a ball of rebar and carefully bent it into a stadium. It seats 91,000 and cost approximately $423 million to build.