Saudi children of al-Fefi family walk up the stairs as they make their way to their schools through Fifa Mountain, in Jazan, south of Saudi Arabia, December 15, 2016. (Photo by Mohamed Al Hwaity/Reuters)

Green algae sits on a beach in Kuwait City, Kuwait, 28 February 2017. The formation of green algae is a normal phenomenon that occurs every year at the shores of Kuwait. (Photo by Raed Qutena/EPA)

People dressed as ancient Roman reflect on a helmet during a parade to mark the anniversary of the foundation of Rome in 753 BC, on April 23, 2017 in Rome, Italy. (Photo by Alberto Pizzoli/AFP Photo)

Hugh Hefner spanks playboy models Izabella Kasprzyk and Bridget Marquardt during their birthday dinner party at Joya restaurant on September 25, 2002 in Beverly Hills, California. Playboy founder and sеxual revolution symbol Hugh Hefner has died at age 91. The magazine released a statement saying Hefner died at his home in Los Angeles of natural causes on Wednesday night, September 27, 2017, surrounded by family. (Photo by David Klein/Getty Images)

In this Thursday, October 5, 2017 photo, Chile's singer-songwriter Mon Laferte performs in concert at the Auditorio Nacional in Mexico City. The 34-year-old artist, who just received five Latin Grammy nominations, performed three sold-out concerts at the National Auditorium, on consecutive evenings, beginning Thursday. (Photo by Eduardo Verdugo/AP Photo)

Passengers wear no trousers as they ride the London Underground in London, Britain, 07 January 2018. The No Pants Subway Ride is an global annual event where people take the public transport while they are not wearing trousers to surprise other passengers. This event takes place on the first Sunday of every year in the world's major cities. (Photo by Tolga Akmen/EPA/EFE/Rex Features/Shutterstock)

Manson Gerasimov of Russia and Agustina Piaggio of Argentina, representing the city of Rio Grande, Argentina, perform during the Stage style final round at the Tango World Championship in Buenos Aires, Argentina on August 23, 2018. (Photo by Marcos Brindicci/Reuters)

U.S. Marines, left, and South Korean Marines, wearing blue headbands on their helmets, take positions after landing on the beach during the joint military combined amphibious exercise, called Ssangyong, part of the Key Resolve and Foal Eagle military exercises, in Pohang, South Korea, Saturday, March 12, 2016. North Korea said Saturday its military is ready to pre-emptively attack and “liberate” the South in its latest outburst against the annual joint military drills by the United States and South Korea. (Photo by Kim Jun-bum/Yonhap via AP Photo)