A Nepalese devotee bows in front of a cow during the 'Gai Puja', also known as the Cow Worship Day, as part of the Tihar festival in Kathmandu, Nepal, 11 November 2015. The Tihar festival is the second most important event for Nepalese Hindus. During the celebrations people worship cows, considered the incarnation of Lord Laxmi, the god of wealth. (Photo by Narendra Shrestha/EPA)

An environmental activist performs during a protest in front of the headquarters of Brazilian mining company Vale SA in downtown Rio de Janeiro, Brazil, November 16, 2015. The collapse of two dams at a Brazilian mine, owned by Vale SA and BHP Billiton Ltd, has cut off drinking water for quarter of a million people and saturated waterways downstream with dense orange sediment that could wreck the ecosystem for years to come. Nine people were killed, 19 are still listed as missing and 500 people were displaced from their homes when the dams burst at an iron ore mine in southeastern Brazil on November 5. (Photo by Sergio Moraes/Reuters)

Winti spiritual leader Ramon Mac-Nack (2nd L) looks on as as his bride Melissa Karwafodi (2nd R) hands a gourd to a Maroon priest (L) as they are wedded in the first Winti marriage ever to be held in public, in district Para, Suriname, November 16, 2015. The Winti religion, which formed centuries ago out of elements of different religious traditions that African slaves brought with them to Suriname, was considered a form idolatry and prohibited by law since the days of slavery until it was finally officially recognized in 1971. (Photo by Ranu Abhelakh/Reuters)

In this November 19, 2015 photo, Ester Melendez feeds banana porridge to her nine-month-old daughter Dina, in Pichiquia, an Ashaninka indigenous community in Peru's Junin region. Incursions and assaults by loggers, miners, colonists and leftist guerrillas have reduced the lands of the Ashaninka people in the Peruvian Amazon, leaving many of the 97,000 members of the group malnourished, despite efforts by the government and independent organizations to help. (Photo by Rodrigo Abd/AP Photo)

An internally displaced woman collects water from a pond to construct a mud-house at the Aboushok camp in El Fasher, North Darfur, Sudan, November 17, 2015. The conflict in Sudan's Darfur region that erupted 12 years ago shows no sign of ending. But it hasn't stopped displaced youngsters, some of whom have spent their entire lives in refugee camps, from dreaming big. Twelve children aged 12 explain their hopes and dreams for the future; ambitions include becoming a doctor, an engineer and a teacher. (Photo by Mohamed Nureldin Abdallah/Reuters)

A Tibetan Buddhist nun spins a prayer wheel in sub zero temperatures at a Buddhist laymen lodge where thousands of people gather for daily chanting session during the Utmost Bliss Dharma Assembly, the last of the four Dharma assemblies at Larung Wuming Buddhist Institute in remote Sertar county, Garze Tibetan Autonomous Prefecture, Sichuan province, China November 1, 2015. (Photo by Damir Sagolj/Reuters)

Ultra Orthodox Jews look at the body of an alleged Palestinian assailant in Jerusalem Saturday, December 26, 2015. According to a police spokeswoman, policemen approached a man who drew their suspicions just outside the Old City for following a pair of Jewish worshippers. Then he pulled out a knife and tried to stab one of them, officers opened fire and killed the assailant. (Photo by Mahmoud Illean/AP Photo)

An injured boy who is undergoing surgery, after he was injured in what activists said was an airstrike by forces loyal to Syria's president Bashar al-Assad, rests inside a field hospital in the Douma neighborhood of Damascus, Syria December 5, 2015. Douma in Syria, an area controlled by rebels fighting to topple President Bashar al-Assad, has been shelled continuously for the past three years. The injured are taken to basements and shelters transformed into field hospitals run by medical staff who have stayed in the battered neighbourhood of Damascus. (Photo by Bassam Khabieh/Reuters)