[lispm]

The Schengen zone means that border controls are at the countries at its border. Everyone who enters the Schengen zone then can move freely to Germany without any controls (exception: flights from non-Schengen countries to Germany). Their are no real border control between the Schengen zone countries.

The Schengen area are has 420 million people. That's like the US + Mexico, but in 26 countries. The US is closing its border to Mexico - Europe has opened up a lot of borders.

But the EU is larger than the Schengen zone. Britain for example is not a part of the Schengen zone, but due to EU law everyone in Britain is free to move to Germany and legally allowed to work here.

Then there are a lot of people in east Europe not in the EU. Many of them under a worse economic and political situation (Ukraine, ...). That motivates a lot of people...