How does the quality of photographs influence our relationship with the past? Plus photographs of the final years of the Russian Empire in vivid color.

Dr. John Mitani, a primatologist at the University of Michigan, answers questions about his research on lethal chimpanzee aggression.

Observations of a group of chimpanzees in Kibale National Park in Kenya show that chimpanzees kill their neighbors to gain dominance and land. What does this tell us about human warfare?

Analysis of DNA extracted from an ancient finger bone points to the existence of a previously unknown type of ancient human that was genetically different from both Neanderthals and modern humans.

Were the Salem Witch Trials sparked by toxic hallucinogens?