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

Kashmiri residents are evacuated in a tractor from their flooded neighborhood in Srinagar, India, Sunday, September 7, 2014. (Photo by Dar Yasin/AP Photo)

Two Scottish shorthair cats dressed with red hats are pictured during a cat exhibition in Bishkek, on October 16, 2016. Cat lovers from Kyrgyzstan, Kazakhstan and Uzbekistan took part in the exhibition. (Photo by Vyacheslav Oseledko/AFP Photo)

Monaco's Princess Charlotte Casiraghi arrives to attend a mass at the Saint Nicholas Cathedral during the celebrations marking Monaco's National Day, on November 19, 2016 in Monaco. (Photo by Valery Hache/Reuters)

A roadside currency exchange vendor sorts Indian currency notes at his stall in Agartala, India, December 6, 2016. (Photo by Jayanta Dey/Reuters)

A woman holds her veil as she takes part in Huranga, a game played between men and women a day after Holi, at Dauji temple near Mathura, March 3, 2018. (Photo by Adnan Abidi/Reuters)

In this Sunday, March 5, 2017 photo, hospitality staff pose for photos on Tiananmen Square during the National People's Congress held at the Great Hall of the People in Beijing. (Photo by Andy Wong/AP Photo)

People spray water in the street ahead of “Songkran”, the annual Thai New Year water-throwing festival, in Kowloon City, Hong Kong, China, 09 April 2017. The pouring of water is a key element in the festival as it represents purification and the washing away of one's sins and bad luck for the year. The event also includes a “Miss Songkran” pageant where contestants are clothed in traditional Thai dress, and a winner is crowned. This year's “Songkran” will begin in Thailand on 13 April 2017. (Photo by Alex Hofford/EPA)