2014 Sydney hostage crisis
After the siege began, a staged exclusion zone was established with thousands of people evacuated from nearby buildings, including from the floors above the café. The Sydney Opera House was evacuated after a suspicious package was found; however, reports were unconfirmed by police. The US Consulate General in Sydney, located in Martin Place, was also evacuated. Some Sydney schools were put in "white level lockout" due to the hostage situation, which meant that no school group was permitted to leave the school grounds.
Siege of Wadi Deif (2014)
The Siege of Wadi Deif refers to the siege of two Syrian Army bases, Wadi Deif and Hamadiyah (both just outside Maarrat al-Nu'man), by rebel forces, during the 2014 Idlib offensive of the Syrian Civil War. The first siege of these two bases was broken by the Syrian Army on 18 April 2013. During the siege, rebels detonated several 'tunnel bombs' underneath Army positions surrounding the bases, which was similar to the tactics used during the First World War.