Why did many migrants travel from Turkey to Greek islands in 2015 and 2016?

During 2015 and 2016, a massive wave of migrants and refugees traveled from Turkey to the Greek islands as they sought to escape turmoil in the Middle East and Africa. For many of these individuals, the Greek islands served as the first stop on a journey toward what they hoped would be a new home in the prosperous countries of northern Europe.12

The migrants typically attempted to reach the islands by making perilous boat crossings. This humanitarian crisis presented a significant challenge for the government of Alexis Tsipras, as Greece struggled to manage the influx. The situation began to change in March 2016, when the European Union and Turkey reached an accord. Under this agreement, Turkey committed to accepting the return of migrants who had reached Greece but failed to apply for asylum or whose requests were denied, which caused the number of migrants attempting the crossing to dissipate quickly.12