Iron

Rankin, Pennsylvania: Built in the 19th century as part of the Homestead Steel Works complex, the Carrie Furnaces produced up to 1,250 tons of iron per day at their peak in the 1950s and '60s.

Most scientists oppose Russ George's efforts to fix the world's climate. But who's going to do something about it?

Worries about oil and gas hog the airwaves. But copper is also essential to keep the world running: It threads through your house, your computer, your eco-correct hybrid car. And it's getting just as difficult, expensive, and environmentally menacing as oil to extract. We have entered the era of tough ore.