A monsoon hiatus that began 4,200 years ago parallels a dry spell that led to the collapse of bronze age civilizations in Egypt, Greece and Mesopotamia
We now have solid evidence that elephants are some of the most intelligent, social and empathic animals around—so how can we justify keeping them in captivity?
Sexy objects encourage people to seek immediate rewards
Concentrations of greenhouse gases in the atmosphere have reached this level for the first time in millions of years. What does this portend?
Competitions like the Firearms Challenge could give guns that use radio-frequency tags, biometrics and other tech a push into the mainstream. Larry Greenemeier reports