Gold has topped a record $900 an ounce. Why is it so precious?

We asked scientists from various fields to help pick the list.

Throughout modern history, the failure to prepare and cope with Mother Nature has resulted in catastrophic consequences, from wrecked economies to thousands of lives lost. Even as modern technology improves forecasts, Nature still gets the upper every now and then. Considering both human and economic costs, we present 10 of the worst all-time disasters to strike the United States. - Tuan C. Nguyen

Many airlines keep their best fare deals for their own Web sites.

Robot uses recorded brainwaves to create interpretive movements of dreams.