Sinkholes are examined. The collapses can be gradual.
Follow the epic operation to secure, raise, and salvage the Costa Concordia cruise ship
Watch as CERN scientists prepare to restart the history-making Large Hadron Collider.
The 1932 kidnapping and killing of Charles Lindbergh's 20-month-old son is revisited. Investigators employ forensic and behavioral science techniques in an effort to learn what happened to the baby and why.