Russia's Ekaterina Birlova casts a shadow on the sand as she serves to Poland during a women's beach volleyball match at the 2016 Summer Olympics in Rio de Janeiro, Brazil, Tuesday, August 9, 2016. (Photo by Marcio Jose Sanchez/AP Photo)

Women walk past a pile of rubbish bags on a street during a strike by garbage collectors demanding delayed salaries in Sanaa, Yemen May 8, 2017. (Photo by Khaled Abdullah/Reuters)

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)

A woman prays as she touches the carcass of a male elephant after he, according to forest officials, was electrocuted early morning in a paddy field on the outskirts of Guwahati, India, June 20, 2017. (Photo by Anuwar Hazarika/Reuters)

A boy and a serviceman pose for a picture during Marines Day celebration in the Black Sea port of Sevastopol, Crimea, November 27, 2016. (Photo by Pavel Rebrov/Reuters)

Traffic police stand at the side of a road in Pyongyang on November 25, 2016. (Photo by Ed Jones/AFP Photo)

A teller at a money changer handles Indonesia rupiah bank notes in Jakarta, Indonesia November 11, 2016. (Photo by Darren Whiteside/Reuters)

An Iraqi special forces Counter Terrorism Service (CTS) member screams during a battle against Islamic State group jihadists (IS) in Mosul's al-Rifaq neighbourhood on January 8, 2017, as an ongoing military operation against the militants continues. Elite Iraqi forces battling the Islamic State group in eastern Mosul reached the Tigris River that splits the city in two for the first time, a spokesman said. (Photo by Dimitar Dilkoff/AFP Photo)