The International Organization for Migration says more than 1 million migrants and refugees have crossed into Europe this year, a symbolic milestone amid the fallout of war, poverty and persecution in Africa and the Middle East.

With just days left in 2015, the Geneva-based intergovernmental organization says the million mark was crossed Monday — marking more than a four-fold increase from last year.

IOM says more than 800,000 crossed into Greece from Turkey, including more than 455,000 from Syria and over 186,000 from Afghanistan. Nearly 3,700 others died trying to cross the Mediterranean in Europe's worst refugee crisis since World War II.

Germany has seen around 1 million migrants arrive this year, but that figure includes large numbers of people from Balkan countries who arrived earlier in 2015.