Some have coined the term "Eurabia" to reflect the large numbers of Muslims now living in Europe.
In Berlin, at the Bundestag - the German parliament, there is an engraving which reads "Dem Deutche Volke' "for the German people."
Just who constitutes the German people, is very much a subject of national debate. While many neighborhoods look traditionally German, in the past 30 years Germany has transformed into a nation of immigrants.
One in five Germans is a first or second generation immigrant. In Europe, only France has more Muslims.
"I think the biggest surprise to Americans who haven't spent time in Europe is that it is much more multi-cultural, much more multi- ethnic than they think. This idea that Europe is this white protestant Christian place is much more complicated than that," said UC Berkeley political science lecturer Amy Gurowitz.
Like America, Germany is wrestling with how best to accommodate its changing demographics. But unlike America, Germany has no national history of integration, no melting pot. The country is home to millions of guest workers who came in the 70s to work, but never became German citizens, and never left.
"The problem is, until the early 90's the immigrants themselves dreamed they would go back. Even within my family, my grandfather was always dreaming of going, my whole family, but they were someone sitting on their luggage, one day we will go," said Ozcan Mutlu from the Berlin Parliament.
Ozcan Mutlu is a member of Berlin's parliament. His heritage is Turkish. He points out only a third of the country's Turks are citizens -- many don't speak German, only a fraction goes on to college. Many do not feel welcome.
"In my country we are at the beginning of this, therefore it is also very difficult for the immigrants to accept themselves as Germans, when the German themselves are in an identity crisis," said Mutlu.
The identity crisis is in part because of reunification. Seventeen years after the fall of the Berlin Wall, Germany struggles to become whole between East and West, it manages 15-percent unemployment, millions of immigrants. Its traditional institutions, like the church are in decline.
It is a country taking beginning steps toward multiculturalism.
In September, the German Parliament tightened up requirements on citizenship. Applicants must now be able to prove they can speak and write German well, and that they are employable and haven't accessed the German welfare system.
German chancellor Angela Merkel has said: "Anyone coming here must tolerate our Western and Christian roots."
She moved recently to pass the most sweeping immigration reforms in German history -- one that will funnel $1 billion dollars a year into integration measures such as language classes, job training and child care.
Her December immigration summit was boycotted by Turkish groups, who protested that the German language requirements don't apply to Americans or Canadians.
Germany has the same issues of forced marriages, head scarves and youth violence as the rest of Western Europe.
One of those arrested in September's terrorist bomb plot was a Turkish national. But Germany has not experienced the large scale intercultural violence that has occured in Britain, Spain and France.
The realpolitik is that Germany needs immigrants to replenish its workforce. Germany has the lowest birthrate in Europe, and without immigrants, Germany's famous social welfare system and the third largest economy in the world will not survive.
