Learning to Navigate a City of Smog

BEIJING -- I never imagined that not long after I moved to Beijing, I would be crawling around on a floor trying to find my apartment building under the glass of a giant map.

But in a city beset by some of the worst pollution in the world, fog, crazy-bad traffic and 22 million people, the map on the third floor of the Beijing Planning Exhibition Hall is a pretty good way to get a sense of where you are.