Two carnival revellers masquerade as Leonardo da Vinci's painting “Mona Lisa” pose in St. Mark's Square in Venice, Italy, Sunday, January 31, 2016. Carnival-goers in Venice are being asked by police to momentarily lift their masks as part of new anti-terrorism measures for the annual festivities. (Photo by Domenico Stinellis/AP Photo)

South Korean rescue members wearing chemical protective suits walk past a monster character (R) during an anti-terror drill as part of a disaster management exercise at the COEX shopping and exhibition center in Seoul on May 20, 2016. South Korea is holding its 2016 Safe Korea anti-disaster exercise this week against terrorist threats and natural disasters. (Photo by Jung Yeon-Je/AFP Photo)

Graduates dance as they take part in a “Last school bell” ceremony at a school in Minsk, Belarus on May 30, 2018. (Photo by Vasily Fedosenko/Reuters)

School cheerleaders wearing protective masks pose for a photo as fellow students arrive for classes on the first day of school in Miami-Dade County at Barbara Goleman Senior High School, in Miami, Florida, August 23, 2021. (Photo by Marco Bello/Reuters)

A Police officer checks a man wearing a carnival costume in Venice, Italy, Sunday, January 31, 2016. Carnival-goers in Venice are being asked by police to momentarily lift their masks as part of new anti-terrorism measures for the annual festivities. Police are also examining backpacks and bags and using metal-detecting wands before revelers are allowed into St. Mark's Square, the heart of the Venetian carnival. (Photo by Luigi Costantini/AP Photo)

In this November 7, 2016 photo, “El Menor”, a member of “Los Cainos” self-defense group formed by the Marval fishing family, holds a homemade gun before starting a night patrol to help protect fishermen from pirate attacks in Punta de Araya, Sucre state, Venezuela. Pirates are terrorizing the coastal state of Sucre, once home to the world's fourth-largest tuna fleet and a thriving fishing industry. (Photo by Rodrigo Abd/AP Photo)

Cottbus Aviation Museum specialists prepare a Soviet Tupolev 134 A passenger plane for dismantlement in Gruenz, Germany, 10 July 2017. The team is preparing the 29 ton plane for transport from a garden in Gruenz to the Aviation Museum in Cottbus. The plane' s owner acquired it in 1991 and transported it with nine tractors and numerous helpers to his vegetable garden where he planned to open a cafe. The plane, formerly used by the East German Stasi for anti- terror operations training, is 30 metres long. (Photo by Jens Büttner/Zentralbild/DPA)

An abandoned tank left by Boko Haram, February 20, 2016, seen on the road to Michika, Nigeria – a town formerly occupied by the insurgents. On April 14, 2014, 300 schoolgirls in the Chibok village in Nigeria were kidnapped by the terrorist group, Boko Haram. Two years later, the majority of these girls are still missing. According to the Global Terrorism Index Report 2015, Boko Haram, which operates mainly in Nigeria, has become the most deadly terrorist group in the world. (Photo by Danielle Villasana)