The one constant that most of the Islamic terrorist attacks have in common is that they kill many innocent people. They often do not target anyone specifically but kill indiscriminately just for the sake of killing.
At least 43 people have been killed in a car bomb blast in the rebel-held Syrian town of Azaz, near the Turkish border, reports say.
The explosion occurred outside a courthouse in the town, some just 7km (four miles) from the Turkish frontier.
Azaz has recently been targeted by so-called Islamic State (IS).
The latest blast is the worst since a nationwide ceasefire – brokered by Russia and Turkey. IS is not included in the truce, which has mainly held.