HANGEDIGI, Turkey—From above, the new border wall separating Turkey from Iran looks like a white snake winding through the barren hills. So far it only covers a third of the 540-kilometer (335-mile) border, leaving plenty of gaps for migrants to slip across in the dead of night.
Traffic on this key migration route from central Asia to Europe has remained relatively stable compared to previous years. But European countries, as well as Turkey, fear the sudden return of Taliban rule in Afghanistan could change that.
