In a valley not far from the Russian-Mongolian border, researchers are exploring royal tombs of the Xiongnu, nomadic tribes that dominated Central Asia for two centuries beginning about 2,300 years ago. Although it is known that these "Huns of Asia" were fierce warriors, knowledge about many aspects of their life is riddled with questions and contradictions.

Researchers have discovered the first known example of a land-based vertebrate that had the ability to fully chew and digest plants. It lived 50 million years before dinosaurs. Chewing is important because it enables animals to break down and efficiently process many different kinds of vegetation.

Researchers studying artifacts recovered from the long-submerged Civil War submarine H.L. Hunley have recovered a long-sought object: a bent gold coin the captain was said to carry as a good-luck piece after it saved him from death by a bullet.

Recent excavations at the Maya city of Chac in Mexico's Yucatán Peninsula shed new light on Mesoamerican prehistory. Data show that the city flourished much earlier than previously thought, and was influenced by the powerful Teotihuacan culture that dominated central Mexico.

A "dog tag" worn by a Union soldier for identification was discovered inside the Confederate submarine H. L. Hunley, archaeologists said Friday. The find baffles researchers, sparking speculation as to why it was found in the sub. Was it a war souvenir, or did it belong to a defector—or a spy?