This category analyses cases involving terrorism, violent extremism, and ideological radicalisation. It explores incidents involving organised terrorist groups, lone-wolf attackers, and individuals influenced by extremist propaganda or political motivations. Each case study reviews how radicalisation occurs, the behavioural indicators that often appear before attacks, and the methods used to recruit individuals into extremist networks. The analysis may also cover intelligence gathering, counter-terrorism operations, and security responses that prevented or responded to attacks. These studies provide valuable insights into how extremist ideologies influence behaviour and how early detection, community awareness, and law enforcement cooperation can help reduce the risk of terrorist incidents.