More than 27,000 migrants have made the perilous crossing to Britain from mainland Europe in 2021, more than three times the total who crossed the Channel in 2020
With the support of EU equipment and personnel, Greece has stepped up security safeguards since the 2015 Paris attacks when jihadists killed 130 people in suicide bombing and gun assaults
Since taking in more than a million people fleeing war and poverty in 2015, Europe has stepped up border controls but still falls short on common migration and asylum policies
The coronavirus outbreak has thrown the plight of Europe's migrant farm workers into stark relief with the added risk of contagion in overcrowded, unsanitary living quarters
A demographic gulf has opened up in Europe since the fall of the Iron Curtain, with migration behind a population decline in many eastern European countries
The wave of refugees fleeing crop failures, droughts and rising sea levels will grow drastically over the next three decades if world governments do not intervene, according to the World Bank.