School teachers and staff members take part during an active shooter training at James I. O'Neill High School in Highland Falls, New York, U.S., December 12, 2017. (Photo by Eduardo Munoz/Reuters)

Two and a half year-old Jennifer Martin in tears during a visit to Santa at Harrods department store in London, 10th December 1949. (Photo by William Vanderson/Fox Photos/Hulton Archive/Getty Images)

Tandem hair drying is possible with a new two-hood attachment for any electric hair dryer manufactured by Postcraft Co of Tucson, Ariz., shown in Chicago, January 27, 1965. A Y adapter permits two hoses to be attached to the dryer. (Photo by Edward Kitch/AP Photo)

A Hindu sadhu (holy man) smears coloured paste onto his face ahead of the forthcoming Hindu festival of “Maha Shivaratri” at the Pashupatinath temple in Kathmandu on February 11, 2018. Hindus mark the “Maha Shivratri” festival by offering special prayers and fasting, with sadhus arriving at Pashupatinath to take part in the event, which takes place on February 13. (Photo by Prakash Mathema/AFP Photo)

Ministry of Defence handout photo of Chinooks from RAF Odiham as they take part in the Royal Air Force flypast over central London to mark the centenary of the RAF on Tuesday, July 10, 2018. (Photo by SAC Pippa Fowles (RAF)/PA Wire)

Participants pose as they take part in a bodybuilding and fitness event named “China Fit”, in Beijing, China, June 15, 2016. (Photo by Reuters/Stringer)

Naki'o, a mixed-breed dog with four prosthetic devices, goes for a run in Colorado Springs April 12, 2013. Naki'o lost all four feet to frostbite when he was abandoned as a puppy in a foreclosed home. (Photo by Rick Wilking/Reuters)

Looters scramble in Philipsburg, St. Maarten, Sunday September 10, 1995 for goods in the Ram's department store, which contained mostly food and liquor. No attempts are currently being made by Dutch troops on the island to stop the looting, since few relief supplies have arrived in St. Maarten, which was ravaged on Tuesday by Hurricane Luis. (Photo by John McConnico/AP Photo)