Couples take part in a competition during a mass wedding of 64 doctoral student couples at Harbin Institute of Technology, a university in Harbin, Heilongjiang province, China, June 4, 2017. (Photo by Reuters/Stringer)

Syrian Internal Security Forces dance in celebration during their graduation ceremony, at Ain Issa desert base, in Raqqa province, northeast Syria, Thursday, July 20, 2017. Some 250 residents of Syria's Raqqa province are the latest batch to graduate from a brief U.S-training course that is preparing an internal security force to hold and secure areas as they are captured from Islamic State militants. (Photo by Hussein Malla/AP Photo)

A female bodybuilder apples oil to another performer backstage before an amateur competition in the Israeli city of Dimona, in this April 3, 2014 file photo. (Photo by Finbarr O'Reilly/Reuters)

A Somali police officer arrests a suspected rebel member of the al Qaeda-affiliated al Shabaab among beach goers in Mogadishu. Al Shabaab claimed responsibility for today's pre-dawn attack on a Kenyan university campus near the Somali border. The following gallery examines who is al Shabaab. Here: Somali police officer (R) arrests a suspected rebel member (L) of the Al Qaeda-affiliated al Shabaab among beach goers at the Lido beach north of Somalia's capital Mogadishu March 23, 2012. (Photo by Feisal Omar/Reuters)

A man flies a kite on the Bund while buildings of Pudong's Lujiazui financial district stand across the Huangpu River as the sun rises in Shanghai, China, on Friday, October 2, 2015. (Photo by Qilai Shen/Bloomberg)

A woman arrives at the Shinto Meiji Shrine to pray on the first day of the new year in Tokyo, Japan, January 1, 2016. (Photo by Thomas Peter/Reuters)

A grey seal basks under a rainbow on a beach on the Lincolnshire coast, England on November 21, 2017. (Photo by Sean Weekly/Caters News Agency)

Picture shows a mural painting in Ferrol, on September 2, 2018, during the annual street art festival “Meninas de Canido” set up in 2008 to breathe new life in a dying neighborhood. Angry at the announced death of his neighborhood, Canido, in Ferrol, Eduardo Hermida painted his version of Velazquez's “Meninas” on a wall. An act of protest that gave birth to a festival and gave new colors to this city of Galicia. (Photo by Miguel Riopa/AFP Photo)