Terrorist attacks are increasingly unpredictable. Manchester provides a key lesson in identifying how the gap between hypothetical plans and the reality of incidents is widening.
How social media is beginning to shape the way the public commemorates tragedies like the Manchester attack.
From spontaneous mass singing after a terror attack to Irish laments, music reflects the painful, complex and laborious task of mourning.
Terrorism is a chameleon by its very nature. Counter-terrorism measures must adapt and ensure a balance of security and liberty.
Child victims are used to justify the cause, while young soldiers further it.
The latest wave of terrorism aims to kill as many people as possible, as horrifically as possible, with new tools and methods. That makes fighting back more difficult.
Security guarantees are impossible, but too many dangerous individuals are falling through the cracks.
And it's not just Muslims who need to start them.
Once we switch from focusing on total terror deaths (or attacks) per country to terror deaths per capita, relevant conclusions about what drives terrorism change dramatically.
The way we talk about attacks is actually helping the extremists' monstrous cause.
Mechanisms such as rhythm, shared emotions and the memory of specific events make music a powerful tool for connecting with other people.
... and that won't make anyone safer in the long run.
Terrorist attacks are more than 'breaking news,' but the media aren't taking a comprehensive approach to exploring the underlying issues.
Research shows that people often become more tolerant.
The construction of a white Christian identity that is threatened by 'outsiders' has a long and troubling legacy.
Like many cities, Manchester can demonstrate strength through diversity, but must face down the forces that would see it divided.
Does the media coverage of the Manchester terrorist attack suggest we are becoming inured to them?
When it comes to Islamist extremism and terrorism, change is a constant.
While this latest storm over intelligence sharing is far from unique, the leaks into the Manchester attack investigation are of a different order.
In the Middle East, tens of millions of young people have few opportunities – and plenty to be angry about.