Hotel staff practice self-defence skills after a training session given by team member of Special Weapons and Tactics (SWAT) team, in Hangzhou, Zhejiang province, April 7, 2016. (Photo by Reuters/Stringer)

Ukrainian state emblem is seen on a gun's holster as soldiers guard naval base in the village of Novoozernoye, some 91 km west of Crimean capital Simferopol, Ukraine, on Monday, March 3, 2014. Ukraine says Russian forces controlling the strategic region of Crimea are demanding that the crew of two Ukrainian warships in Sevastopol's harbor must surrender. (Photo by Ivan Sekretarev/AP Photo)

A homeless street child looks in the window of a car in Jammu, India, Friday, January 6, 2017. Some 800 million people in the country live in poverty, many of them migrating to big cities in search of a livelihood and often ending up on the streets. (Photo by Channi Anand/AP Photo)

The finishing touches are made to a new wax figure of Theresa May at Madame Tussauds in London, England on November 7, 2017. (Photo by Victoria Jones/PA Wire)

Dancers perform during a general rehearsal of “Kreatur” (Creature) by German choreographer Sasha Waltz in collaboration with artist and fashion designer Iris van Herpen and light designer Urs Schoenebaum in Berlin, Germany on June 8, 2017. (Photo by Stefanie Loos/Reuters)

The Mausoleum of the Giants, an immersive solo show of monumental sculptures by the artist Phlegm, is installed at Taylor’s Eye Witness Works in Sheffield, England on March 14, 2019. (Photo by Danny Lawson/PA Wire Press Association)

Nature, singles winner: Frogs with their legs severed struggle to the surface, surrounded by frogspawn, after being thrown back into the water in Covasna, Romania. (Photo by Bence Mate/World Press Photo 2019)

A fellow officer comes to the aid of injured patrolman C.V. Satt, who was pelted with rocks and beer bottles during a clash between police and relief demonstrators in Denver September 23, 1935. (Photo by Henry G. Eisenhand/AP Photo)