Devastating 2001 events symbolize terrorism for many Americans, causing them to underestimate risk for homegrown, far-right extremism, experts say

As trial gets going, it is not clear if Hayat Boumeddiene, on the run since her partner killed a cop and four Jews in 2015 terror attacks, is dead or alive

Iraqi man, 30, arrested after causing series of crashes, wounding 6, reportedly shouting 'Allahu Akbar' and appearing to falsely indicate he had a bomb

Spike of nearly 8,000 mainly due to inclusion of members of far-right Alternative for Germany party; number of far-left and Islamic extremists each up by some 1,500

Judges reject appeal by al Qaeda-linked suspect accused of war crimes in Timbuktu, paving way for July court date

Uber driver tells undercover officers that he was planning attacks on several targets, including Madame Tussauds, a tour bus and the London pride parade

Instagram stars, former Victoria's Secret models, and Hollywood actors travel to Riyadh for three-day musical extravaganza

Britain has been struck by a series of attacks over past decade and a half, many of them claimed by jihadists

Homeland Security says it is at 'heightened' vigilance; British authorities reportedly increase monitoring of extremist suspects; Egyptian, Philippine authorities boost precautions

While social media giant says it is gaining control over prohibited content, whistleblower's complaint says success rates are lower than claimed