A terrorism expert and psychologist explains what sets people onto the path of extremism.

From the cradle of civilization in Mesopotamia to Constantinople, researchers from Yale have mapped urban settlements from 3700 B.C. to 2000 A.D.

The rise of ISIS, continuous drone strikes, and the lack of a powerful leader could spell the demise of the terrorist group.

Peter Piot and his peers co-discovered Ebola in 1976. We speak with the pandemic expert about the global health community’s response to Zika.

Law enforcement is trying to draw the line between sympathizers and terrorists, and the Internet is making it even harder to pin it down.

Millennials worry about inequality, but don’t frame it in economic terms.