Actors perform a scene in a film directed by Humam Husari in the rebel-held besieged town of Zamalka, in the Damascus suburbs, Syria September 19, 2016. (Photo by Bassam Khabieh/Reuters)

South Korea's Black Eagles aerobatics team perform a maneuver during a preview of the Singapore Airshow at Changi exhibition center in Singapore February 14, 2016. The Airshow will take place from February 16-21. (Photo by Edgar Su/Reuters)

India's Border Security Force (BSF) soldiers ride their camels during a rehearsal for the “Beating the Retreat” ceremony in New Delhi, India, January 27, 2016. The ceremony symbolises retreat after a day on the battlefield, and marks the official end of the Indian Republic Day celebrations. It is held every year on January 29. (Photo by Anindito Mukherjee/Reuters)

A staff interacts with a white lioness in a private zoo called “12 Months” in the town of Demydiv, Ukraine, January 13, 2016. (Photo by Gleb Garanich/Reuters)

An artist performs in water during a dress rehearsal for “Amaluna”, a show by Cirque du Soleil, at the Royal Albert Hall in London, Britain January 15, 2016. (Photo by Dylan Martinez/Reuters)

A tribal Fulani man milks a cow at a local milk collecting centre in Dangwala Karfi village on the outskirts of Nigeria's northern city of Kano January 19, 2016. (Photo by Akintunde Akinleye/Reuters)

Mask dancers take part in a parade during the the International Festival of Masquerade Games “Surva” in the town of Pernik, some 30 km from Sofia, Bulgaria, January 31, 2016. (Photo by Vassil Donev/EPA)

A vendor prepares paan, a betel nut-based chewable stimulant at a flower market in Kolkata, India, January 18, 2016. (Photo by Rupak De Chowdhuri/Reuters)