Unraided crypts are hard to come by. And yet in 1968, soldiers stumbled upon the imperial family tombs of a Han dynasty ...

Similar weapons with smelted iron blades suggest meteoritic metal could have informed early ironworking techniques. PHOTO: ZHAO ANG, GUO STATE MUSEUM, SANMENXIA, CHINA BACKGROUND: OWEN FREEMAN ...

Archaeologists think this innovation was independently discovered in several places and then spread through the ancient world ... heating and hammering cast iron to remove impurities and add ...