Some of London's telephone operators and engineers, trying out their gas masks at the anti-gas civilian training centre in Gloucester, where they were taught how to deal with gas attacks. (Photo by Harry Todd/Fox Photos/Getty Images). 13th February 1937

A member of the Eton public school O.T.C. (Officers Training Corps) practising shouting out orders during a training session, 20th January 1940. (Photo by Hulton Archive/Getty Images)

“Horst Ludwig Wessel (October 9, 1907 – February 23, 1930) was a German Nazi activist who was made a posthumous hero of the Nazi movement following his violent death in 1930. He was the author of the lyrics to the song “Die Fahne hoch” (“The Flag On High”), usually known as Horst-Wessel-Lied (“The Horst Wessel Song”), which became the Nazi Party anthem and, de facto, Germany's co-national anthem from 1933 to 1945”. – Wikipedia

Photo: German Nazi activist Horst Wessel (left) at the head of a parade of S.A. stormtroopers, or “brownshirts”, in Nuremberg, Germany, 1929. (Photo by Hulton Archive/Getty Images)

Ravi Nath poses for a photograph with a cobra snake in Jogi Dera (Snake charmers settlement), in the village of Baghpur, in the central state of Uttar Pradesh, India November 10, 2016. An ancient tribe of snake charmers, known as Saperas, have thrived over the generations by catching venomous snakes and making them dance to their music. Snakes are revered by Hindus in India and snake charmers are considered the followers of Lord Shiva, the blue-skinned Hindu god who is usually portrayed wearing a king cobra around his neck. (Photo by Adnan Abidi/Reuters)

France's Simon Billy gets ready to practice speed skiing on the Chabriere ski slope in Vars, on March 29, 2017. (Photo by Jean-Pierre Clatot/AFP Photo)

An officer of the Afghan border police throws an assault rifle to a policeman participating in a military exercise on the outskirts of Herat, Afghanistan, Monday, September 7, 2015. Twelve female and seventy male border police personnel participated in the military exercise near the border with Iran in Herat province. (Photo by Hoshang Hashimi/AP Photo)

A street vendor spreads vermilion powder used for worship during the Tihar festival, also called Diwali in Kathmandu, Nepal, November 9, 2015. Hindus all over Nepal are celebrating the Tihar festival during which they worship cows, which are considered a maternal figure, and other animals. Also known as the festival of lights, devotees also worship the goddess of wealth Laxmi by illuminating and decorating their homes using garlands, oil lamps, candles and colourful light bulbs. (Photo by Navesh Chitrakar/Reuters)

A Christian worshipper reacts as she takes part in the Christian Orthodox Holy Fire ceremony at the Church of the Holy Sepulchre in Jerusalem's Old City, April 30, 2016. (Photo by Amir Cohen/Reuters)