Sumgayit, Azerbaijan

Number of people potentially affected: 275,000
Type of pollutant: Organic chemicals, oil and heavy metals
Source of pollution: Petrochemical and industrial complexes

Another legacy of the Soviet Union's utter disregard for the environment — Stalin once boasted that he could correct nature's mistakes —Sumgayit's many factories, while they were operational, released as much as 120,000 tons of harmful emissions, including mercury, into the air every year. Most of the factories have been shut down, but the pollutants remain — and no one is stepping up to take responsibility for them. "It's a huge, abandoned industrial wasteland," says Fuller.

— by Bryan Walsh