Flowers, candles and messages left by mourners adorn a tree near the spot where Maria L., a 19-year-old medical student, was raped and murdered on December 8, 2016 in Freiburg im Breisgau, Germany. Police have arrested Hussein K., a refugee from Afghanistan who was 16 at the time of the October murder, after identifying him through CCTV camera images and DNA evidence. The likely fact that a refugee is responsible for the murder has grown into a poltical issue, with a local branch of the right-wing AfD (Alternative fuer Deutschland) political party quick to point a finger at what they deem as Germany's over-liberal policy on admitting over one million refugees and migrants since 2015. Meanwhile critics have blasted German television station ARD for failing to report on the arrest in its Tagesschau news broadcast in what many right-leaning analysts see as pro-refugee bias by the media.  (Photo by Sean Gallup/Getty Images)

Sean Gallup/Getty

Flowers, candles and messages left by mourners adorn a tree near the spot where Maria L., a 19-year-old medical student, was raped and murdered in Freiburg im Breisgau, Germany. Photo by Sean Gallup/Getty Images

A picture of Syria's President Bashar al-Assad is seen in Ramouseh, a government controlled area of Aleppo, Syria December 8, 2016. REUTERS/Omar Sanadiki

Omar Sanadiki/Reuters

A picture of Syria’s President Bashar al-Assad is seen in Ramouseh, a government controlled area of Aleppo, Syria. Omar Sanadiki/Reuters 

Iraqi internally displaced groom Jassim Mohammed walks with his bride, Amena Ali, during their wedding ceremony at a camp for internally displaced people, in Khazir, near Mosul, Iraq, Thursday, Dec. 8, 2016.  Iraqi forces have pushed IS out of most of Anbar over the past year, and are now waging a major offensive in the northern city of Mosul, the militant group's last major urban bastion in the country. (AP Photo/Hadi Mizban)

Hadi Mizban/AP

Iraqi internally displaced groom Jassim Mohammed walks with his bride, Amena Ali, during their wedding ceremony at a camp for internally displaced people, in Khazir, near Mosul, Iraq. Hadi Mizban/AP

A Kenyan nurse shouts slogans in a march outside the Ministry of Health headquarters during their strike following the failed negotiations between health unions and government on wage increases and improvement of working conditions in Nairobi, Kenya December 8, 2016. REUTERS/Thomas Mukoya

Thomas Mukoya/Reuters

A Kenyan nurse shouts slogans in a march outside the Ministry of Health headquarters during their strike following the failed negotiations between health unions and government on wage increases and improvement of working conditions in Nairobi, Kenya Photo Thomas Mukoya/Reuters 

A general view of the conveyor belts and systems that handle the hundreds of thousands of items of mail that pass through the Royal Mail's Worldwide Distribution Centre on December 8, 2016 in Slough, England. The festive season sees a huge spike in postal items coming through the centre from all over the United Kingdom, destined for international destinations.  (Photo by Leon Neal/Getty Images)

Leon Neal/Getty Images

A general view of the conveyor belts and systems that handle the hundreds of thousands of items of mail that pass through the Royal Mail’s Worldwide Distribution Centre in Slough, England. The festive season sees a huge spike in postal items coming through the centre from all over the United Kingdom, destined for international destinations. Photo by Leon Neal/Getty Images

Iraqi soldiers distribute water to children outside a distribution point run by United Nations agencies at Zahra district, east of Mosul, Iraq December 8, 2016. REUTERS/Ahmed Jadallah.

Ahmed Jadallah/Reuters

Iraqi soldiers distribute water to children outside a distribution point run by United Nations agencies at Zahra district, east of Mosul, Iraq. Photo Ahmed Jadallah/Reuters 

British Police officers stand on duty outside the Supreme Court in London on the final day of a four-day hearing on December 8, 2016. British Prime Minister Theresa May secured a symbolic victory on Brexit yesterday, after MPs agreed not to delay her plans to begin the EU exit talks by the end of March, although she had to promise to give them more details of her negotiating strategy. The House of Commons vote is not binding and the government is still fighting a challenge at the Supreme Court against moves to give parliament the final say on starting the Brexit process. / AFP PHOTO / Justin TALLISJUSTIN TALLIS/AFP/Getty Images

Justin Tallis/AFP/Getty

British Police officers stand on duty outside the Supreme Court in London on the final day of a four-day hearing to appeal against the High Court ruling that Article 50 can not be triggered without a Parliamentary vote. Photo Justin Tallis/AFP/Getty 

epa05665245 Aerial view of Paris with the Eiffel tower shrouded in haze, in Paris, France, 08 December 2016. Paris is undergoing a third day pollution spike, prompting the city to limit vehicle circulation.  EPA/YOAN VALAT

Yoan Valat/EPA

An aerial view of Paris with the Eiffel tower shrouded in haze, in Paris, France. Paris is undergoing a third day pollution spike, prompting the city to limit vehicle circulation. Yoan Valat/EPA 

An Indian Sikh devotee takes a dip in the holy sarovar (water tank) during dense fog at the Golden Temple in Amritsar on December 9, 2016. / AFP PHOTO / Narinder NANUNARINDER NANU/AFP/Getty Images

Narinder Nanu/AFP/Getty

An Indian Sikh devotee takes a dip in the holy sarovar during dense fog at the Golden Temple in Amritsar. PhotoNarinder Nanu/AFP/Getty 

Lawmakers and members of opposition parties hold cards during a rally demanding the impeachment of South Korean President Park Geun-hye at the National Assembly in Seoul, South Korea, Wednesday, Dec. 7, 2016. Park, who faces impeachment this week, rose to power with the support of conservatives enamored of the economic growth ushered in by her late dictator father decades ago. The sign read "President Park Geun-hye" and "Impeachment !". (AP Photo/Ahn Young-joon)

Ahn Young-joon/AP

Lawmakers and members of opposition parties hold cards during a rally demanding the impeachment of South Korean President Park Geun-hye at the National Assembly in Seoul, South Korea. Photo Ahn Young-joon/AP 

A bull shark swims at the Ocearium in Le Croisic, western France, on December 6, 2016.     / AFP PHOTO / LOIC VENANCELOIC VENANCE/AFP/Getty Images

Loic Venance/AFP/Getty

A bull shark swims at the Ocearium in Le Croisic, western France. Photo Loic Venance/AFP/Getty

A member of the Syrian government forces inspects a post used by the rebels in the newly captured Al-Safa neighbourhood of Aleppo on December 7, 2016. Rebels in Aleppo called for a five-day truce and the evacuation of civilians Wednesday after losing more than three quarters of their territory including the Old City to a Syrian army offensive.

George Ourfalian/AFP/Getty

A member of the Syrian government forces inspects a post used by the rebels in the newly captured Al-Safa neighbourhood of Aleppo. Photo George Ourfalian/AFP/Getty 

Newly appointed French Prime Minister Bernard Cazeneuve talks to journalists on December 7, 2016 after their first cabinet meeting at the Elysee Palace in Paris. / AFP PHOTO / Patrick KOVARIKPATRICK KOVARIK/AFP/Getty Images

Patrick Kovarik/AFP/Getty

Newly appointed French Prime Minister Bernard Cazeneuve talks to journalists after their first cabinet meeting at the Elysee Palace in Paris. Photo Patrick Kovarik/AFP/Getty 

Iraqi forces backed by tribal militias during battle to retake a village from the Islamic State on the eastern bank of the river Tigris, Iraq December 7, 2016. REUTERS/Mohammed Salem

Mohammed Salem/Reuters

Iraqi forces backed by tribal militias during battle to retake a village from the Islamic State on the eastern bank of the river Tigris, Iraq. Photo Mohammed Salem/Reuters 

Police officers look on as a firework thrown by protesters explodes in front of them in the central district of Exarchia in Athens, on December 6, 2016, following a commemorative rally marking the eighth anniversary of the killing of teenager Alexandros Grigoropoulos by a Greek police officer.   Hundreds of  pupils, university students and workers  participated in  a  rally to mark the eighth anniversary of the fatal police shooting of a 15-years old student , which sparked riots in the country in 2008.    / AFP PHOTO / ARIS MESSINISARIS MESSINIS/AFP/Getty Images

Aris Messinis/AFP/Getty

Police officers look on as a firework thrown by protesters explodes in front of them in the central district of Exarchia in Athens following a commemorative rally marking the eighth anniversary of the killing of teenager Alexandros Grigoropoulos by a Greek police officer. Photo Aris Messinis/AFP/Getty 

Lionel Bonaventure/AFP/Getty

Outgoing French Prime Minister Manuel Valls waves as he leaves the Hotel Matignon in a car, in Paris during the handover ceremony after he resigned to seek the Socialist nomination in next year’s presidential election. Photo Lionel Bonaventure/AFP/Getty

A child walks in front of Iraqi army during an operation against Islamic State militants in the neighbourhood of Intisar, eastern Mosul, Iraq, December 6, 2016. REUTERS/Ahmed Jadallah

Ahmed Jadallah/Reuters

A child walks in front of Iraqi army during an operation against Islamic State militants in the neighbourhood of Intisar, eastern Mosul, Iraq. Photo Ahmed Jadallah/Reuters 

Migratory birds of the flamingo species congregate at the shore of Kuwait City, Kuwait, 06 December 2016. Flamingos and other migratory birds are having regular appearances on the coast at the beginning of warm winter in Kuwait.  EPA/RAED QUTENA

Raed Quetena/EPA

Migratory birds of the flamingo species congregate at the shore of Kuwait City. Flamingos and other migratory birds are having regular appearances on the coast at the beginning of warm winter in Kuwait. Photo Raed Quetena/EPA 

German Chancellor and leader of the conservative CDU Merkel reacts after her speech at the CDU party convention in Essen

Kai Pfaffenbach/Reuters

German Chancellor and leader of the conservative Christian Democratic Union party CDU Angela Merkel reacts after her speech at the CDU party convention in Essen, Germany. Photo Kai Pfaffenbach/Reuters 

British Prime Minister Theresa May addresses sailors on board HMS Ocean during her trip to attend the Gulf Cooperation Council summit in Bahrain, on December 6, 2016 in Manama, Bahrain. Prime Minister May is the first British leader and the first woman to attend the annual two-day Gulf Cooperation Council and will attend a dinner with the leaders of Saudi Arabia, Kuwait, the United Arab Emirates, Qatar, Bahrain and Oman on Tuesday, and will also discuss the situation in Yemen and Syria.  (Photo by Carl Court/Getty Images)

Carl Court/Getty Images

British Prime Minister Theresa May addresses sailors on board HMS Ocean during her trip to attend the Gulf Cooperation Council summit in Manama, Bahrain. Photo Carl Court/Getty Images