A massive influx of migrants to Europe over the past few years has left thousands drowned and caused deep tensions between nations over how to handle the huge number of arrivals. Here is a look back over the main developments since 2011.
2011 to 2014: Surge with Syria at war
The surge in migrant numbers starts in 2011 and steadily increases until 2014 when 280,000 arrive, four times more than the previous year. Most land in Italy and Greece.
The UN High Commissioner for Refugees (UNHCR) says more than 3,500 people, fleeing war and misery, died at sea in 2014 alone, mainly in the central Mediterranean.
The conflict in Syria, which started in March 2011, leads to a massive exodus of people, mostly to camps in neighbouring countries.
The UNHCR says in October 2014 that just over 144,630 Syrians had requested asylum in the EU since 2011, with Germany and Sweden shouldering the burden.
It says in June 2014 that 2.5 million people had fled Syria. By April 2018 this figure is at more than 5.6 million, according to the UNHCR website.
2015: More than one million migrants
The International Organization for Migration (IOM) says 1,047,000 migrants arrived by sea in Europe in 2015, of whom around 854,000 went to Greece and 154,000 to Italy.
The increase is due to the raging Syrian conflict and a deterioration in living conditions in refugee camps.
On April 19, 2015 the worst Mediterranean disaster in decades takes place when up to 800 people, mainly from West Africa, die after their crammed fishing boat capsizes in Libyan waters.
In 2015 nearly 3,800 deaths at sea are registered by the UNHCR.
The war in Syria is credited with kick-starting a wave of migrant movement