Climate change is a big worry in Latin America, Asia and Africa, but ISIS makes more Europeans and North Americans anxious.
World leaders joined voices to condemn the French and Tunisian terrorist attacks during Ramadan, calling them barbaric and appalling.
ISIS sympathizers are growing via the Internet, and provocations like the event in Texas don't help.
Smaller terrorist groups are tougher to stop, but they also tend to cause less damage.
Copenhagen police said a man shot dead by officers was responsible for two fatal attacks that shocked the normally peaceful Danish capital.
Solo-working experts and secrecy are a recipe for disaster, experts warn, when it comes to hunting terrorists.
Hundreds of thousands of people joined by world leaders flooded Paris on Sunday in a historic show of defiance and solidarity against terrorism following this week's Islamist attacks in the French capital.
Genes primarily affecting males, as well as family environment help explain why so many terrorists and killers are men, including brothers.
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