Joe Deedon, president of TAC ONE Consulting, demonstrates searching for a shooter in a middle school during an Active Shooter Response course offered by TAC ONE in Denver April 2, 2016. According to TAC ONE, the course, which is offered for the first time to concealed weapons permit carrying civilians, is designed at preparing people to effectively save lives prior to the arrival of law enforcement at an active shooter incident. (Photo by Rick Wilking/Reuters)

South Korean teenagers participate in a warfare exercise as part of the Special Warfare Command's training course at a military base on August 4, 2011 in Seoul, South Korea. About 1,000 civilian volunteers including middle and high school students participated in the special force's four-day training programme to develop their spiritual and physical strength. (Photo by Chung Sung-Jun/Getty Images)

In this photo distributed by the Israeli Defense Forces (IDF) May 23, 2005, woman soldiers wear branches in their helmets as their infantry instructors' course learns about camouflage during the field craft week of their training May 19, 2005 at an army base near Beersheva in Israel's southern desert. It takes the IDF more than 2 months to teach these 18-year-old female recruits the basic arts of warfare before they assigned to pass on their newly-acquired skills to the army's male and female draftees. (Photo by Abir Sultan/IDF via Getty Images)

These hyper realistic drawings are so lifelike they could pass for photographs. The incredibly detailed works of art were created by self-taught artist Ivan Hoo, from Singapore, who earns a living from his realistic drawings and paintings. The 31-year-old takes up to three days to complete the impressive pieces, which include animal portraits and still life drawings of everyday items such as a Starbucks cup. The A3 sketches are completed using a range of soft pastel pencils and are drawn from still life, or a photograph taken by Ivan himself. Here: Ivan Hoos drawing of a pug. (Photo by Ivan Hoo/Caters News)

Trainees of the Tianjiao Special Guard/Security Consultant bodyguard training camp watch their instructor use a scarf to cover a student's head during a demonstration of close-quarter combat skills at a special course on flight safety inside a scale model of a passenger jet at a flight attendant training centre on the outskirts of Beijing, March 18, 2014. Inspired by the missing Malaysia Airlines Flight MH370, the company wanted to emphasize the importance of aviation safety by teaching their trainees emergency evacuation procedures and close-quarter combat skills to handle situations such as natural disasters and plane hijacks, according to the company. (Photo by Jason Lee/Reuters)

Islamic female students practice the ancient Thai art of “Krabi Krabong” taught as a sport at the Darunsat Wittaya school on August 16, 2011 in Saraburi, Thailand. (Photo by Paula Bronstein/Getty Images)

Undated David Yarrow handout photo of a gorilla as the self-taught wildlife photographer promotes his book, Encounter. (Photo by David Yarrow/Clearview/PA Wire)

Meet the star students of orangutan school – the unique rehab centre where orphaned apes are taught how to climb trees and survive in the wild without their mum and dad. (Photo by Caters News)