The IOC is worried about Beijing's air pollution
Beijing Olympic Bird's Nest ready
The main venue for Beijing's Olympic Games - the "Bird's Nest" stadium - is complete and fully operational, Chinese officials have said.
The 91,000-seat stadium will host the Olympics' opening and closing ceremonies as well as athletics events.
A network of steel girders gives the stadium its nest-like appearance. All 37 venues for the Games are now ready.
The International Olympic Committee has praised Beijing's preparations, but said air quality was a concern.
The Bird's Nest - or National Stadium - was designed by award-winning Swiss firm Herzog and de Meuron and Chinese architect Li Xinggang.
The design beat dozens of other entries in a worldwide competition held in 2003.
"The Bird's Nest is the last completed Olympic venue but the best," said project manager Tan Xiaochun.
The project was completed at a cost of $500m (£250m).
"You can imagine yourself to be an athlete, standing at the centre of the venue attracting thousands of eyes," said Li Xinggang.
"You will be turned on by the audience's cheers, feeling at the centre of a stage. It will lead you to final success."