A man from Dinka tribe holds his AK-47 rifle in front of cows in a Dinka cattle herders camp near Rumbek, capital of the Lakes State in central South Sudan December 14, 2013. (Photo by Goran Tomasevic/Reuters)

Employees of a food stand take pictures of Titan, a robot created by England Cyberstein Robots, performing at the Danilovsly market in downtown of Moscow, Russia, 12 May 2014. Titan visited to Moscow to attend “Bal Robotov”, an interactive exhibition of the most recent advances in robotics which will be opened on 15 May in Artplay Moscow exhibition center. Titan worked alongside superstars including Will.i.am, Rihanna, Will Smith and Jackie Chan. (Photo by Sergei Ilnitsky/EPA)

Participants lay down on a street covered by coloured powder during the annual Bangkok Color Run in Bangkok, Thailand April 1, 2017. (Photo by Athit Perawongmetha/Reuters)

A Christian pilgrim is baptised by a priest in the muddy water of the Jordan River at the Kasser-Al-Yahud baptismal site near the West Bank city of Jericho, on April 11, 2017. According to the gospels Jesus Christ was baptised in the waters of the Jordan River by John the Baptist. (Photo by Gali Tibbon/AFP Photo)

Singer Rita Ora enters her hotel on April 27, 2017 in New York City. (Photo by MEGA)

This picture taken with an underwater camera shows Japan' s Yumi Adachi competing in the Mixed Duet technical final during the synchronised swimming competition at the 2017 FINA World Championships in Budapest, on July 17, 2017. (Photo by Bernadett Szabo/Reuters)

A man with blood on his shirt is evacuated from Brussels Airport in Zaventem, Belgium, on Tuesday, March 22, 2016. (Photo by Dirk Waem/Belga/Zuma Press/TNS)

An ethnic Armenian fighter carries Kalashnikov machine guns to his comrade-in-arms at Martakert province in the separatist region of Nagorno-Karabakh, Azerbaijan, Monday, April 4, 2016. (Photo by Vahan Stepanyan/PAN Photo via AP Photo)