A member of the mainly Christian “anti-balaka” (anti-machete) militia trains in the Boeing neighbourhood of Bangui, Central African Republic, on February 24, 2014. (Photo by Fred Dufour/AFP Photo)

People in costume take photos during a Halloween event on October 31, 2015 in Lan Kwai Fong, Central District, Hong Kong. Halloween, a named taken from 'All Hallows' Even' falls on the day before All Saints' Day on November 1, a holiday when Christians remember their deceased loved ones. (Photo by Jerome Favre/Getty Images)

A woman carrying cabbage leaves on her head buys tomato at a market in Ahmedabad, India, November 9, 2015. India's villages face a sharp spike in food prices in 2016, as a second year of drought drives up the cost of ingredients such as sugar and milk, and poor transport infrastructure stops falling global prices from reaching rural areas. (Photo by Amit Dave/Reuters)

“Thunderstruck”. Summer stom. A super cell formed off the coast of New Zealand, intensified and swept across Christchurch and North Canterbury, February 23, 2014. Photo location: Christchurch, New Zealand. (Photo and caption by David Hardy/National Geographic Photo Contest)

People walk through crop circles in a cornfield near Raisting, Germany, on July 28, 2014. According to media reports, a balloonist had discovered the circle some days ago. Since then, hundreds of people came to the field to watch it, however it is unclear who did create the pattern. (Photo by Karl-Josef Hildenbrand/DPA)

People carrying red umbrellas march through downtown Skopje, Macedonia, marking the International Day to End Violence against s*x Workers, Thursday, December 17, 2015. A group of s*x workers, supported by members of non-government organizations, rallied Thursday demanding rights for the s*x workers and destigmatization of their profession. The banner reads: The Stigma Kills. (Photo by Boris Grdanoski/AP Photo)

Balinese girls in traditional costumes gather during a parade for this year's last sundown in Bali island, Indonesia Thursday, December 31, 2015. (Photo by Firdia Lisnawati/AP Photo)

A pole-dancing robot built by British artist Giles Walker performs at a gentlemen's club Monday, January 8, 2018, in Las Vegas. The event was held to coincide with CES International. (Photo by Jae C. Hong/AP Photo)