2014 Sydney hostage crisis
The 2014 Sydney hostage crisis, also known as the Sydney siege and Lindt Cafe siege, occurred on 15–16 December 2014 when a lone gunman, Man Haron Monis, held hostage ten customers and eight employees of a Lindt chocolate café located at Martin Place in Sydney, Australia. Police treated the event as a terrorist attack at the time, but Monis' motives were subsequently debated. However, the findings of the Coroner in 2017 deemed the event to be a terrorist attack.
Siege
A siege occurs when an attacker encounters a city or fortress that cannot be easily taken by a quick assault, and which refuses to surrender. Sieges involve surrounding the target to block the provision of supplies and the reinforcement or escape of troops (a tactic known as "investment"). This is typically coupled with attempts to reduce the fortifications by means of siege engines, artillery bombardment, mining (also known as sapping), or the use of deception or treachery to bypass defenses.