A Bengal tiger licks a glass enclosure during a presentation of Bengial tiger cubs at the Malabon Zoo in Malabon City, north of Manila, Philippines, 14 July 2016. The Bengal tiger cubs, which were born at the zoo, are two months old and named “Tiger Duterte” and “Tiger Leni”. The Malabon Zoo has one of the largest private collections of exotic and endemic animals in the Philippines. (Photo by Mark R. Cristino/EPA)

Saintsetseg Jambaldorj, a member of the Tsaatan ethnic minority, one of the last remaining groups of nomadic reindeer herders in East Taiga, Mongolia, wearing a traditional deel, on July 5, 2016. (Photo by Madoka Ikegami/Barcroft Images)

Students celebrate their A-level results at King Edward VI High School for Girls in Birmingham, England on August 18, 2016. The proportion of top grades achieved by A-level students across the UK has fallen for a fifth year in a row, and girls have caught up with boys in attaining A* grades. (Photo by Joe Giddens/PA Wire)

Actress Kat Dennings arrives at the premiere of Paramount Pictures' and Marvel's “Thor” held at the El Capitan Theatre on May 2, 2011 in Los Angeles, California. (Photo by Kevin Winter/Getty Images)

A picture made available on 17 July 2015 shows the bright line of the Milky Way above the old oaks at the Rogalin landscape Park in Rogalin village, near Poznan, on the night of 16 July 2015. (Photo by Lukasz Ogrodowczyk/EPA)

A trader speaks on the phone at his desk at the Frankfurt stock exchange, Germany, in this June 29, 2015 file photo. Federal Reserve policymakers are widely seen raising interest rates for the first time in almost a decade at their next meeting this week. (Photo by Ralph Orlowski/Reuters)

A Thai traffic security guard wears a Santa Claus costume as he directs the traffic on a street during Christmas celebrations outside a shopping mall in Bangkok, Thailand, 22 December 2015. The campaign of a shopping mall is held to celebrate the upcoming Christmas season and to attract shoppers. (Photo by Narong Sangnak/EPA)

Kazakh troops march during a parade of the armed forces to mark the Defender of the Fatherland Day in Astana, May 7, 2014. (Photo by Mukhtar Kholdorbekov/Reuters)