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)

People look at a tanker after it fell into a caved-in area on a road in Xi'an, Shaanxi province, July 27, 2013. No casualty was reported in the accident, according to local media. (Photo by Reuters/Stringer)

ESA astronaut Tim Peake posted this stunning image on his social media channels, commenting: “Station passed through magnificent aurora Australis last night”. Tim is set to return to Earth on 18 June 2016, bringing his six-month Principia mission to the ISS to an end. During his stay he performed more than 30 scientific experiments for ESA and taking part in numerous others from ESA's international partners. ESA and the UK Space Agency have partnered to develop many exciting educational activities around the Principia mission, aimed at sparking the interest of young children in science and space. (Photo by Tim Peake/ESA/NASA)

An African immigrant tries to jump a fence into a ferry terminal in the western Greek town of Patras April 28, 2015. Afghan, Iranian and Sudanese immigrants, living precariously in abandoned factories in Patras, southwest Greece, try to stow away on nearby ferries to Italy as they seek a better life in Europe beyond crisis-hit Greece. (Photo by Yannis Behrakis/Reuters)

Wildlife agency rangers rescue a Malayan tapir, an endangered species on the International Union for Conservation of Nature (IUCN) Red List, after it fell into a villager's fish pond in Pekanbaru, Riau on April 20, 2021. (Photo by Wahyudi/AFP Photo)

Revellers make the most of Friday night in Soho, central London after the hottest day of the year recorded in the capital this year, June 17, 2022. (Photo by Marcin Nowak/Alamy Live News)

The Soyuz 2.1b rocket with a Fregat-M booster and meteorology and emergency communications satellite Arktika-M No 1 launches from Baikonur Cosmodrome in Baikonur, Kazakhstan on February 28, 2021. Arktika-M No 1 is the first of ten Arktika satellites to be launched by Roscosmos into orbit. (Photo by Roscomos/TASS)

Girls embrace in front of a makeshift memorial for victims by the Covenant School building at the Covenant Presbyterian Church following a shooting, in Nashville, Tennessee, March 28, 2023. A heavily armed former student killed three young children and three staff in what appeared to be a carefully planned attack at a private elementary school in Nashville on Monday, before being shot dead by police Chief of Police John Drake named the suspect as Audrey Hale, 28, who the officer later said identified as transgender. (Photo by Brendan Smialowski/AFP Photo)