A couple hugs while standing near a Christmas tree made out of plastic bins and plastic hampers outside the Museum of History in Monterrey, Mexico, December 4, 2015. The humble Christmas tree has a rich history, from evergreen trees used to symbolise eternal life in Ancient Egypt to tree worship among pagan Europeans. The modern version has its origins in Germany, where the song “O Tannenbaum” is still a festive favourite. Today the traditional tree with lights and decorations appears in cities including Washington, Moscow and Beirut. Alternative constructions range from recycled rubbish in Mexico City to old window frames in Rakvere, Estonia. Whatever the shape or size, the message is the same: Merry Christmas. (Photo by Neil Hall/Reuters)

A suspected Vietcong is kicked by a Vietnamese soldier holding a rifle as another soldier attempts to tie his hands on October 22, 1965. The prisoner was one of 15 captured October 21 near Xom Chua when government troops raided in the plain of reeds area. Troops killed 43 suspected Vietcong and seized some arms. (Photo by Richard Merron/AP Photo)

People gather at the site of a train derailment near Beni Suef, Egypt, Thursday, February 11, 2016 that injured dozens of people were injured as it was traveling north toward Cairo. Railroad accidents due to negligence are common in Egypt. Egyptians have long complained that the government has failed to deal with the country's chronic transport problems. (Photo by Samer Abdallah/AP Photo)

A pair of tigers soak in a shallow pool at Tiger Temple, a Buddhist monastery where paying visitors can interact with young adult tigers, in Kanchanaburi, Thailand, March 16, 2016. The attraction, near the Myanmar border, started collecting the animals 15 years ago when villagers brought an injured tiger cub to the local abbot, who agreed to care for it. Today there are nearly 150 tigers at the monastery. (Photo by Amanda Mustard/The New York Times)

In this March 17, 2015 photo, Ashaninka Indian men, identified by locals as illegal loggers, tie tree trunks together to move them along the Putaya River near the hamlet of Saweto, Peru. Illegal logging persists unabated in this remote Amazon community where four indigenous leaders who resisted it were slain in September. The Putaya River is the waterway that transports felled trees, cut both legally and illegally, to the city of Pucallpa. (Photo by Martin Mejia/AP Photo)

In this Monday, March 16, 2015 photo, Syrian refugee Samira Helal, 17, who is two months pregnant, poses for a portrait at inside her tent at an informal tented settlement near the Syrian border, on the outskirts of Mafraq, Jordan. Nearly 3.8 million Syrians have fled their country and are now registered as refugees, according to the U.N. Most face increasingly desperate circumstances. (Photo by Muhammed Muheisen/AP Photo)

A female Kurdistan Workers Party (PKK) fighter stands near a security position in Sinjar, March 13, 2015. Women fighters at a Kurdistan Workers Party (PKK) base on Mount Sinjar in northwest Iraq, just like their male counterparts, have to be ready for action at any time. Smoke from the front line, marking their battle against Islamic State, which launched an assault on northern Iraq last summer, is visible from the base. Many of the women have cut links with their families back home; the fighters come from all corners of the Kurdish region. (Photo by Asmaa Waguih /Reuters)

Nestled among the cocoa plantations of western Ivory Coast is a gold mine that does not feature on any official maps. It is not run by an industrial mining company, nor does it pay taxes to the central government. The unlicensed mine is a key part of a lucrative business empire headed by the deputy commander of the West African nation's elite Republican Guard, United Nations investigators allege. Here: A gold prospector sits and eats close to a soldier at a gold mine near the village of Gamina, in western Ivory Coast, March 18, 2015. (Photo by Luc Gnago/Reuters)