ATHENS, Greece — Bitter cold, biting winds and rough winter seas have done little to stem the seemingly endless flow of desperate people fleeing war or poverty for what they hope will be a brighter, safer future in Europe. As 2016 dawns, boatloads continue to reach Greek shores and thousands trudge across Balkan fields and country roads heading north.

More than a million people reached Europe in 2015 in the continent’s largest refugee influx since the end of World War II — a crisis that has tested European unity and threatened the vision of a borderless continent.