In all of these cases the weapon of choice was a vehicle, driven at speed, into crowds innocently going about their daily business. Barcelona is just the latest in a series of targets of Islamic terrorism over the past year in which a vehicle has been used to mow down those in its path indiscriminately.
In all of these cases Islamic State (IS) has claimed responsibility.
These sorts of terrorist attacks – like the 2001 al-Qaeda plane attacks on targets in New York and Washington – have elevated threats to the civilian population in urban areas to a new level.
In the latest