A look at what may have caused a massive landslide.
The terra-cotta army of Chinese emperor Qin Shi Huang.
Follow the paleontologists who are reconstructing a terrifying carnivore dubbed Spinosaurus.
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.