cities

Berliners may soon get more to see on the horizon than just construction cranes, if a German architect realizes his massive vision. The world's largest artificial mountain could sit on the spot currently occupied by Tempelhof airport, and provide a natural getaway for Berliners and tourists alike. Did we also mention the fine skiing opportunities from September through March?

Architect Jakob Tigges has named his 1,000-meter-tall mountain "The Berg," which may conjure up images of some bygone World War II-era redoubt. But the idea supposedly has many supporters among Berlin residents, and we have to admit that it's a novel way of one-upping all those other cities focused on having the tallest buildings.

You may already know about the pollution plight of Linfen, China. But how about the heavy metals Pittsburghers breathe in on a daily basis? Or the incomparable smog Milanesi put up with? PopSci has culled an eye-opening selection of some of the world's most problematic cities. From the painfully high cancer rates in Sumgayit, Azerbaijan to the acid rain destroying La Oroya, Peru, writer Jason Daley will walk you through the lowest of the low; and explain why, despite it all, there's still hope for these places.