Armed Syrian Turkmen villagers are seen near the northern Syrian village of Yamadi, near the Turkish-Syrian border, Syria, November 24, 2015. Turkey shot down a Russian warplane near the Syrian border on Tuesday saying it had repeatedly violated its air space, one of the most serious publicly acknowledged clashes between a NATO member country and Russia for half a century. (Photo by Reuters/Stringer)

Gerald Herbert is a staff photographer for the AP based in New Orleans, Louisiana. Before that he was a staff photographer for the Washington Times, the New York Daily News and a freelancer for the AP in New Orleans, Boston and New York. Photo: A worker grooms away tracks after an alligator crossed through a sand trap on the 14th hole during the first round of the PGA Tour Zurich Classic golf tournament at TPC Louisiana in Avondale, La., Thursday, April 25, 2013. (Photo by Gerald Herbert/AP Photo)

In this photo taken Wednesday, November 26, 2014 attack dogs and their handlers apprehend a “rhino poacher” center, after alighting from a helicopter into water, in a simulation exercise showing training at an academy run by the Paramount Group, near Rustenburg, South Africa. The course prepares canine units to find firearms or contraband, track suspects in the undergrowth and abseil in harnesses from helicopters in pursuit of poachers. Dogs and handlers learn to trust each other and fine tune a relationship balancing control and aggression. (Photo by Denis Farrell/AP Photo)

Tsar Alexander II (1818–1881) known as “The Liberator” lying in state. He was mortally wounded by an assassination attack in St Petersburg. (Photo by Hulton Archive/Getty Images). March 1881

A boy crawls under a cow during a religious ceremony celebrating the Tihar festival, also called Diwali, in Kathmandu, October 23, 2014. Hindus all over Nepal are celebrating the festival during which they worship cows, which are considered a maternal figure, and other animals. Also known as the festival of lights, devotees worship the goddess of wealth Laxmi by illuminating and decorating their homes using garlands, oil lamps, candles and colourful light bulbs. (Photo by Navesh Chitrakar/Reuters)

A woman tries to protect her daughter as refugees scuffle with the Greek police in their effort to reach the borderline with Macedonia, near the Greek village of Idomeni, Sunday, November 22, 2015. Over 1,000 migrants gathered in the Greek town Idomeni protested Saturday against the decision by Macedonian authorities across the border to turn away migrants who are not from war zones such as Syria, Afghanistan and Iraq. (Photo by Giannis Papanikos/AP Photo)

Breitling Wingwalkers aircrafts perform during an aerobatic display at an air show in Zhengzhou, Henan province, China, September 25, 201. (Photo by Reuters/Stringer)

A woman in traditional Malaysian attire welcomes leaders to the official dinner at the venue of the Association of Southeast Asian Nations (ASEAN) Summit in Kuala Lumpur, Malaysia November 21, 2015. (Photo by Jorge Silva/Reuters)