Recently, there has been some confusion over reports heard on Fox News about "no-go" zones in European cities. Make no mistake: They do exist, and they are real. Soeren Kern has an article in the Gatestone Institute which describes these areas.
The reason they exist in Europe and not in the US is that the Europeans brought in millions of workers from Islamic countries along with their families and paid no attention to the idea of assimilation assuming they would stay temporally and eventually leave. However, instead of leaving, they remained and had more children who are now the disaffected and unassimilated ones. In contrast, most of our Muslim immigrants came as educated experienced people. They became doctors, nurses, engineers, and they moved into neighborhoods with everyone else. In that respect, they became assimilated. Their children are now in the universities. The problem is that some of these children are caught up in world events and becoming radicalized. To add to our situation, tens of thousands of people have arrived here as refugees from places like Somalia. That is also true in Europe.
We need to watch what happens in Europe carefully. It is a textbook example of how not to do immigration.