A boat filled with refugees and migrants, mostly from Syria, arrives on the shores of Lesbos, Greece, after crossing the Aegean Sea from Turkey on December 4, 2015. 
       
     
 A father comforts his crying son shortly after arriving on the shores of Lesbos, Greece, on November 17, 2015. 
       
     
 A mountain of discarded lifejackets used by refugees and migrants crossing the Aegean Sea are seen at a dump on Lesbos, Greece, on December 3, 2015. 
       
     
 A rubber dingy, packed with refugees mostly from Syria, is assisted to shore in Lesbos, Greece, on November 16, 2015, after having crossed the Aegean Sea from Turkey. Nearby is a small wooden boat previously used by other refugees arriving in Greece. 
       
     
 A father carries his son off a rubber dinghy after arriving on the island of Lesbos, Greece, on November 12, 2015. 
       
     
 A Yazidi refugee washes her daughter in the sea shortly after arriving on Lesbos, Greece, on November 13, 2015. After a long journey, the toddler was badly in need of a wash and clean diapers. 
       
     
 Kurdish refugees warm themselves on the beach shortly after arriving on the shores of Lesbos, Greece, after crossing the Aegean Sea from Turkey on December 8, 2015.    
       
     
 Volunteers attempt to assist a small wooden boat, packed with refugees, to shore in Lesbos, Greece, on November 16, 2015. 
       
     
 A refugee family, with nothing but the clothes on their backs, makes the several kilometers walk towards a transit center in Lesbos, Greece, on November 12, 2015, shortly after making the crossing from Turkey.
       
     
 Refugees prepare to camp in the open near a registration center at the Moria transit camp in Lesbos, Greece, on November 13, 2015.
       
     
 Refugees and migrants from Afghanistan and Syria wait for registration numbers at the Moria transit camp in Lesbos, Greece, on November 16, 2015. 
       
     
 A family salvages a baby carriage near the border between Greece and the Former Yugoslav Republic of Macedonia on December 10, 2015.
       
     
 Refugees and migrants wait to cross the border between Greece and the Former Yugoslav Republic of Macedonia on December 10, 2015.
       
     
 Hundreds of refugees and migrants wait to board a ferry from Mytilini, Lesbos, to Athens, after receiving their registration papers on December 8, 2015.    
       
     
 A family sleeps wherever they can find space on the ferry from Lesbos to Athens on December 19, 2015. Because many refugee families cannot afford regular priced seats, they are forced to opt for the cheapest tickets for the 10 hour ferry ride.
       
     
 An Afghan family prepares their belongings before disembarking the ferry they took from Lesbos to Athens on December 19, 2015 as the ship approaches Greece's capital. From there, refugees will take buses to the Greece-Macedonia border where they will continue their journey into Western Europe. 
       
     
 Tariq, left, Nisreen, and their five-year old daughter Roslyn, are seen on the day-long bus ride from Athens to the Greek-Macedonian border in the far north, as they continue their journey from Syria to Germany, on December 19, 2015. 
       
     
 Refugees warm themselves by a self-made fire during another long stop at a roadside pit-stop on the journey from Athens to the Greek-Macedonian border on December 19, 2015. 
       
     
 Amer and Nali warm themselves with blankets and tea, provided by volunteers, shortly before crossing the border between Greece and Macedonia on December 20, 2015. 
       
     
 Refugees are seen walking on the railway tracks on the Macedonian side shortly after crossing the border between Greece and Macedonia on December 20, 2015. 
       
     
 A refugee family warms themselves by a fire whilst waiting to cross the Greek-Macedonian border in Idomeni on December 20, 2015. 
       
     
 A boat filled with refugees and migrants, mostly from Syria, arrives on the shores of Lesbos, Greece, after crossing the Aegean Sea from Turkey on December 4, 2015. 
       
     

A boat filled with refugees and migrants, mostly from Syria, arrives on the shores of Lesbos, Greece, after crossing the Aegean Sea from Turkey on December 4, 2015. 

 A father comforts his crying son shortly after arriving on the shores of Lesbos, Greece, on November 17, 2015. 
       
     

A father comforts his crying son shortly after arriving on the shores of Lesbos, Greece, on November 17, 2015. 

 A mountain of discarded lifejackets used by refugees and migrants crossing the Aegean Sea are seen at a dump on Lesbos, Greece, on December 3, 2015. 
       
     

A mountain of discarded lifejackets used by refugees and migrants crossing the Aegean Sea are seen at a dump on Lesbos, Greece, on December 3, 2015. 

 A rubber dingy, packed with refugees mostly from Syria, is assisted to shore in Lesbos, Greece, on November 16, 2015, after having crossed the Aegean Sea from Turkey. Nearby is a small wooden boat previously used by other refugees arriving in Greece. 
       
     

A rubber dingy, packed with refugees mostly from Syria, is assisted to shore in Lesbos, Greece, on November 16, 2015, after having crossed the Aegean Sea from Turkey. Nearby is a small wooden boat previously used by other refugees arriving in Greece. 

 A father carries his son off a rubber dinghy after arriving on the island of Lesbos, Greece, on November 12, 2015. 
       
     

A father carries his son off a rubber dinghy after arriving on the island of Lesbos, Greece, on November 12, 2015. 

 A Yazidi refugee washes her daughter in the sea shortly after arriving on Lesbos, Greece, on November 13, 2015. After a long journey, the toddler was badly in need of a wash and clean diapers. 
       
     

A Yazidi refugee washes her daughter in the sea shortly after arriving on Lesbos, Greece, on November 13, 2015. After a long journey, the toddler was badly in need of a wash and clean diapers. 

 Kurdish refugees warm themselves on the beach shortly after arriving on the shores of Lesbos, Greece, after crossing the Aegean Sea from Turkey on December 8, 2015.    
       
     

Kurdish refugees warm themselves on the beach shortly after arriving on the shores of Lesbos, Greece, after crossing the Aegean Sea from Turkey on December 8, 2015. 

 

 Volunteers attempt to assist a small wooden boat, packed with refugees, to shore in Lesbos, Greece, on November 16, 2015. 
       
     

Volunteers attempt to assist a small wooden boat, packed with refugees, to shore in Lesbos, Greece, on November 16, 2015. 

 A refugee family, with nothing but the clothes on their backs, makes the several kilometers walk towards a transit center in Lesbos, Greece, on November 12, 2015, shortly after making the crossing from Turkey.
       
     

A refugee family, with nothing but the clothes on their backs, makes the several kilometers walk towards a transit center in Lesbos, Greece, on November 12, 2015, shortly after making the crossing from Turkey.

 Refugees prepare to camp in the open near a registration center at the Moria transit camp in Lesbos, Greece, on November 13, 2015.
       
     

Refugees prepare to camp in the open near a registration center at the Moria transit camp in Lesbos, Greece, on November 13, 2015.

 Refugees and migrants from Afghanistan and Syria wait for registration numbers at the Moria transit camp in Lesbos, Greece, on November 16, 2015. 
       
     

Refugees and migrants from Afghanistan and Syria wait for registration numbers at the Moria transit camp in Lesbos, Greece, on November 16, 2015. 

 A family salvages a baby carriage near the border between Greece and the Former Yugoslav Republic of Macedonia on December 10, 2015.
       
     

A family salvages a baby carriage near the border between Greece and the Former Yugoslav Republic of Macedonia on December 10, 2015.

 Refugees and migrants wait to cross the border between Greece and the Former Yugoslav Republic of Macedonia on December 10, 2015.
       
     

Refugees and migrants wait to cross the border between Greece and the Former Yugoslav Republic of Macedonia on December 10, 2015.

 Hundreds of refugees and migrants wait to board a ferry from Mytilini, Lesbos, to Athens, after receiving their registration papers on December 8, 2015.    
       
     

Hundreds of refugees and migrants wait to board a ferry from Mytilini, Lesbos, to Athens, after receiving their registration papers on December 8, 2015. 

 

 A family sleeps wherever they can find space on the ferry from Lesbos to Athens on December 19, 2015. Because many refugee families cannot afford regular priced seats, they are forced to opt for the cheapest tickets for the 10 hour ferry ride.
       
     

A family sleeps wherever they can find space on the ferry from Lesbos to Athens on December 19, 2015. Because many refugee families cannot afford regular priced seats, they are forced to opt for the cheapest tickets for the 10 hour ferry ride.

 An Afghan family prepares their belongings before disembarking the ferry they took from Lesbos to Athens on December 19, 2015 as the ship approaches Greece's capital. From there, refugees will take buses to the Greece-Macedonia border where they will continue their journey into Western Europe. 
       
     

An Afghan family prepares their belongings before disembarking the ferry they took from Lesbos to Athens on December 19, 2015 as the ship approaches Greece's capital. From there, refugees will take buses to the Greece-Macedonia border where they will continue their journey into Western Europe. 

 Tariq, left, Nisreen, and their five-year old daughter Roslyn, are seen on the day-long bus ride from Athens to the Greek-Macedonian border in the far north, as they continue their journey from Syria to Germany, on December 19, 2015. 
       
     

Tariq, left, Nisreen, and their five-year old daughter Roslyn, are seen on the day-long bus ride from Athens to the Greek-Macedonian border in the far north, as they continue their journey from Syria to Germany, on December 19, 2015. 

 Refugees warm themselves by a self-made fire during another long stop at a roadside pit-stop on the journey from Athens to the Greek-Macedonian border on December 19, 2015. 
       
     

Refugees warm themselves by a self-made fire during another long stop at a roadside pit-stop on the journey from Athens to the Greek-Macedonian border on December 19, 2015. 

 Amer and Nali warm themselves with blankets and tea, provided by volunteers, shortly before crossing the border between Greece and Macedonia on December 20, 2015. 
       
     

Amer and Nali warm themselves with blankets and tea, provided by volunteers, shortly before crossing the border between Greece and Macedonia on December 20, 2015. 

 Refugees are seen walking on the railway tracks on the Macedonian side shortly after crossing the border between Greece and Macedonia on December 20, 2015. 
       
     

Refugees are seen walking on the railway tracks on the Macedonian side shortly after crossing the border between Greece and Macedonia on December 20, 2015. 

 A refugee family warms themselves by a fire whilst waiting to cross the Greek-Macedonian border in Idomeni on December 20, 2015. 
       
     

A refugee family warms themselves by a fire whilst waiting to cross the Greek-Macedonian border in Idomeni on December 20, 2015.