The most recent attacks in Manchester, London, Paris or Berlin were carried out by lone assailants, their links to larger international terror groups still being investigated. But large or small, terrorists are striking across the EU. New security measures have been put in place, with extra police on the streets, more checks on luggage and more scans to walk through.
There is also a new frontier in the fight against terrorism: a virtual one. Governments are looking to gain access to our online communications. Calls for bringing an end to encrypted messages are growing. As control over social media is stepped up, Europol says the Islamic State group is also adapting and is now looking to develop its own social media platform.
So how secure can we be in today's world? Both online and off, are there mesures that could or should be put in place?
Presented by Eve Irvine.
Produced by Isabelle Romero and Anais Guérard.