Russian honor guard soldiers warm up prior a rehearsal for the Victory Day military parade in St. Petersburg, Russia, Wednesday, May 3, 2017. The parade will take place at Dvortsovaya (Palace) Square on May 9, to celebrate 72 years after the victory in WWII. (Photo by Dmitri Lovetsky/AP Photo)

British sailors taking shore leave on the British dependency of Gibraltar visit the Suiza Bar to watch a Spanish dancer perform on August 05, 1954. These Spanish entertainers are under contract and must return over the border by 11 o'clock. (Photo by Bert Hardy/Getty Images)

Public Space series, 2015. This series by Morteza Niknahad and Behnam Zakeri tends toward cinema, taking an almost cartoonish view of modern life in Iran. This work was inspired by the social life of dolphins. (Photo by Morteza Niknahad and Behnam Zakeri/The Guardian)

A couple takes a selfie as Hoa Binh hydroelectric power plant opens the flood gates after a heavy rainfall caused by Talas typhoon in Hoa Binh province, outside Hanoi, Vietnam July 20, 2017. (Photo by Reuters/Kham)

Festival-goers take a bath in a mud pool during the 20th Boryeong Mud Festival on Daecheon beach in Boryeong City, some 190 kilometers west of Seoul, South Korea, 22 July 2017. Tourists flock to the area to experience the beneficial properties of the Boryeong mud, as well as for a variety of entertainment events. The festival runs from 21 until 30 July. (Photo by Jeon Heon-Kyun/EPA/EFE)

Assam's Veerangana commandos take part in a rehearsal for India's Republic Day parade at Khanapara in Guwahati, India January 23, 2017. India celebrates its annual Republic Day on January 26. (Photo by Anuwar Hazarika/Reuters)

U.S. Democratic presidential candidate Hillary Clinton takes a photo with supporters John Nelson, 32, (L) and Dan Stifler, 32, (C) after speaking at the UFCW Union Local 324 in Buena Park, California, U.S. May 25, 2016. (Photo by Lucy Nicholson/Reuters)

Competitors take part in the Christmas Really Wild Mud Run on a 4.6 miles course across undulating farm land at Celtic Camping, St David's, Pembrokeshire, Wales, December 12, 2015. (Photo by Rebecca Naden/Reuters)