Here's Beijing as it looks on a "blue sky" day, with the usual smog lifted from the city's skyline by a nice dry wind.

No, it's not a SARS epidemic--just a hazy day in Beijing, where a white mask is standard commuter wear.

The Beijing National Aquatic Center is the greenest site of the games, as well as the coolest looking. The outer surface and roof were designed to catch tens of thousands of tons of rainwater per year, not to fill the pool, but to clean the building and surrounding areas.

Beijing's Olympic water rerouting plan hasn't been popular with Heibing Province farmers like Tao Qun, who had to give up his land--parched as it was--to make way for a special reservoir to feed the Olympics.

Chinese authorities tout their success in cleaning up the Qinghe River in North Beijing, reducing pollution by two-thirds since 2004. Here, the new Metro 5 subway line--also built in time for the Olympics--crosses the sparkling water.

Despite cleanup efforts, plenty of rivers in China still look like this one, the Han River.

As part of its Olympic cleanup, Beijing replaced its diesel buses with the world's largest fleet of natural gas buses, which spew fewer emissions.

For all of its efforts to expand public transportation, Beijing's streets are nevertheless choked with traffic--including 1,300 new cars a day.

Beijing's new National Indoor Stadium is largely solar-powered, as part of a push to keep the games' carbon footprint to a minimum.

An international symbol of unity--and a carbon nightmare. The world's most jetset flame spews as much carbon in its four-month trip as the average American--in two lifetimes.