Europe is being invaded. The invaders don't generally carry weapons. Instead, one arrives in a European city, settles into the generous welfare benefits with the help of European social workers and other bureaucrats, then sends for the REST of the family.
Bring ten kids, no problem! Bring Granny and Grandpa, too. Take over an abandoned building, claim you are an independent business but can't make ends meet, get income supplements from the German government, for example.
These modern invaders are amazed how easy it is. Read the excellent article from Germany linked below.