A new generation is drilling for steam, capturing the sun with giant mirrors and harnessing the wind; why the largest North American hydro plant is underground; the innovators of tomorrow's power sources.

Featured: crosscut saws; haggis; collectible firearms.

Featured: clay liquor jugs; poultry deli meats; NASCAR engines.

The most expensive public works project ever in California, crews are racing to earthquake-proof the San Francisco-Oakland Bay Bridge before the next Big One.

Featured: marbles; water filter; tool boxes; packing foam.