A riot policeman watches as a police vehicle burns in Braamfontein, Johannesburg, South Africa, Tuesday, October 25, 2016. Rioters in South Africa set a police vehicle on fire Tuesday and stoned vehicles near a Johannesburg university that has been the scene of sometimes violent protests by students demanding free education. The violence broke out in streets near the University of the Witwatersrand at around the same time that student protesters met and marched off the campus, South African media reported. (Photo by Yeshiel Panchia/AP Photo)

In this photo taken on Friday, July 14, 2017, a student at a paramilitary camp for children calls the rank to attention outside Kiev, Ukraine. As the deadly conflict in eastern Ukraine entered its third year, some parents in Ukraine are anxious to make sure their children are ready to fight it, instead of swimming and playing volleyball. (Photo by Efrem Lukatsky/AP Photo)

In this Thursday, March 17, 2016 photo, 33-year-old Palestinian clown doctor Alaa Miqdad, left, entertains 3-year-old patient Yaqin Shawaf, who suffers from dialysis, in the department of kidney diseases at Al-Rantisi children's hospital in Gaza City. (Photo by Adel Hana/AP Photo)

A woman waits at a polio immunisation health centre, in Maiduguri, Borno State, Nigeria, August 29, 2016. Nigeria's military has liberated large swathes of land from Boko Haram but a ride with an army convoy, all guns firing for fear of ambush, shows how far the northeast is from normality after a brutal Islamist insurgency that has displaced millions. (Photo by Afolabi Sotunde/Reuters)

Eight year-old Maya Mohammad Ali Merhi walks using prosthetic legs made by her father from tin cans in a camp for displaced people, in the northern Syrian province of Idlib on June 20, 2018. Maya and her father were both born without lower limbs. Unable to afford real prosthetic limbs, her father made her a pair out of tin cans filled with cotton and scrap pieces of cloth. Maya's family had to leave their home in the Aleppo province to flee battles. (Photo by Aaref Watad/AFP Photo)

The unromantic gypsies. Children boxing in a gypsy camp in Kent, England on July 1, 1951. Like all boys these gypsy lads like to try their hand at boxing. Encouraged by their friends they fight it out on Corke's Meadow. Few Romanies now live a life of wandering romance. Most are like the three hundred squatters of Corke's Meadow, Kent, which is part of a “gypsy problem” that involves about 100,000 today. Of those about 25,000 can be rightly called gypsies, the rest are Mumpers and Posh-rats and Hobos. Corke's Meadow has both kinds. “Picture Post” cameraman Bert Hardy photographs the Corke's Meadow gypsies in their encampment. (Photo by Hulton-Deutsch Collection/Corbis via Getty Images)

A Mongolian Shamaness or Buu, beats her drum while taking part with others in a fire ritual meant to summon spirits to mark the period of the Summer Solstice in the grasslands on June 22, 2018 outside Ulaanbaatar, Mongolia. Banned for 70 years under Communist rule, shamanism has seen a resurgence in Mongolia since 1992, when the ancient practice became protected by the country's Constitution. Known as Tengrism, in which Shamans channel ancestral spirits, it is widely regarded as Mongolia's national religion and part of its indigenous identity. (Photo by Kevin Frayer/Getty Images)

A woman sweeps an alleyway adorned with murals painted by artists from “Delhi Street Art” group at the Raghubir Nagar slum in New Delhi on December 2, 2019. A New Delhi slum has been given a colourful makeover thanks to a street artist collective, drawing art lovers and selfie-snappers to a rundown area that they would never normally visit. (Photo by Sajjad Hussain/AFP Photo)