NPR Story
1:00 pm
Mon December 12, 2011

Megacities: Scars On The Earth, Or Keys To Growth?

Critics have long derided the world's biggest cities as disorderly, overcrowded and polluted. But in recent years, as the planet's population continues to rise past seven billion and more and more people flock to urban areas, some now argue that cities may hold the key to sustainable growth.