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)

Visitors and a dog stand on the new “Skywalk” viewing platform on the Sonnenstein mountain in the Eichsfeld region near Bad Lauterberg im Harz, central Germany, on May 22, 2017. (Photo by Martin Schutt/AFP Photo/DPA)

Demonstrators clash with members of the Bolivarian National Police as protests continue in Caracas, Venezuela, 20 April 2017. The Bolivarian National Guard, using tear gas, tried to disperse protests against the government of Venezuelan President Nicolas Maduro. (Photo by Miguel Gutierrez/EPA)

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)

Models walk in the finale of the Jeremy Scott Fall 2016 collection during Fashion Week in New York, Monday, February 15, 2016. (Photo by Richard Drew/AP Photo)

A woman wearing leggings with the colours of the US flag walks along a street of Havana on February 18, 2015. President Barack Obama announced Thursday he will make a landmark visit to Cuba on March 21-22, pledging to address human rights as America pursues a historic thaw with its former Cold War foe. (Photo by Yamil Lage/AFP Photo)

Hotel staff practice self-defence skills after a training session given by team member of Special Weapons and Tactics (SWAT) team, in Hangzhou, Zhejiang province, April 7, 2016. (Photo by Reuters/Stringer)

A masked Burundian protester faces soldiers in front of a burning barricade during an anti-government demonstration against President Pierre Nkurunziza's bid for a third term in the capital Bujumbura, Burundi, 25 May 2015. Street protests continued on 25 May as the United Nations Secretary-General Ban Ki-moon condemned the killing of the leader of the oppsition party Union for Peace and Development (UPD) Zedi Feruzi who opposed Nkurunziza's bid. (Photo by Dai Kurokawa/EPA)