Men cover their heads from the sun while riding on a motorcycle during a hot day in Cairo, Egypt, August 17, 2015. A heatwave killed at least 61 people across Egypt from Sunday to Tuesday and caused nearly 600 people to be admitted to hospital, Egypt's health ministry said on state news agency MENA on Wednesday. (Photo by Amr Abdallah Dalsh/Reuters)

Robert Burck, a street performer known as “The Naked Cowboy” dips a woman as he poses for a photo in Times Square in New York, U.S., August 4, 2016. (Photo by Carlo Allegri/Reuters)

A woman weeps after an announcement that Thailand's King Bhumibol Adulyadej has died, at the Siriraj hospital in Bangkok, Thailand, October 13, 2016. Thailand's Royal Palace says King Bhumibol, the world's longest-reigning monarch, has died at age 88. (Photo by Athit Perawongmetha/Reuters)

A woman smokes a cigar as she reads the newspaper in a street of Havana, on November 26, 2016, the day after Cuban revolutionary leader Fidel Castro died aged 90. One of the world's longest-serving rulers and modern history's most singular characters, Castro defied 11 US administrations and hundreds of assassination attempts. (Photo by Yamil Lage/AFP Photo)

“Left behind” children Luo Hongni, 11 (L) and brother Luo Gan,10, carry flowers to be used as feed while doing chores in the fields on December 18, 2016 in Anshun, China. Like millions of Chinese children, the four Luo siblings are being raised by their grandparents in rural China as their parents left to find work in urban areas. (Photo by Kevin Frayer/Getty Images)

Ali Asair, who has left his family behind and traveled hundreds of kilometers in search for a pasture for his animals, attends to his camel in a pastoralists' settlement in the Bandarbeyla district in Somalia's semi-autonomous region of Puntland, Somalia, 24 March 2017. According to media reports, the United Nations says only 31 percent of 864 million US dollars appeal for a drought-hit Somalia is funded. The UN said the world is facing the largest humanitarian crisis since 1945, adding that more than 20 million people are facing the threat of famine in Somalia, Yemen, South Sudan and Nigeria and 1.4 million children could die from starvation this year. (Photo by Dai Kurokawa/EPA)

People enjoying the races on a wet day at Chester Racecourse on May 12, 2017 in Chester, England. (Photo by Alan Crowhurst/Getty Images)

In this April 1, 2002, file photo, Mike Cole, of Jenkintown, Pa., right, performs a kick-flip over a trash can with his skateboard as tourists pose for photos in front of artist Robert Indiana's sculpture in John F. Kennedy Plaza, also known as Love Park, in Philadelphia. Granite slabs from Philadelphia's famed Love Park, a skateboarding mecca though for a long stretch an illegal one, are being shipped in 2017 to the city of Malmo, Sweden, nearly 4,000 miles away, for use in construction of a skate park there. (Photo by Douglas Bovitt/AP Photo)