The EU and Turkey have reached a deal on the migrant crisis, which will see migrants returned to Turkey in exchange for aid and political concessions.
Under the plan, from midnight Sunday migrants arriving in Greece will be sent back to Turkey if their asylum claim is rejected.
In return, EU countries will resettle Syrian migrants living in Turkey.
EU leaders have welcomed the agreement but German Chancellor Angela Merkel warned of legal challenges to come.
Some of the initial concessions offered to Turkey have been watered down and some EU members expressed disquiet over Turkey's human rights record.
Despite this Turkish Prime Minister Ahmet Davutoglu said it was a "historic" day.
"We today realised that Turkey and the EU have the same destiny, the same challenges and the same future."
European Council President Donald Tusk said there had been unanimous agreement between Turkey and the 28 EU members.
It is hoped the plan will deter people from taking the often dangerous sea crossing from Turkey to Greece.
