From the BBC:
Europe’s border-free zone expands
Border controls drop along the old Iron Curtain, but are beefed up in the east.
If you want to take a few ferryboats, you can drive from Oslo to Tallinn to Warsaw to Berlin to Madrid to Rome to Athens to Valletta without passing a border checkpoint. Austria and Hungary are together again. Switzerland is going to join the zone next year. But people going from Estonia to Russia have greater problems now.
It’s funny how you get used to no border controls. I was in Esztergom on the Hungary - Slovakia border recently and decided to stroll across the bridge over the Danube, because how many Westerners can say they’ve been to Slovakia? (It seemed very much like Hungary, to be honest). I was a little surprised to arrive at a Checkpoint Charlie and had to hunt around in my backpack for my passport. They accepted Hungarian money in the little border town over the river, and I saw plenty of Hungarian licence plates, but you still had to log in and out when you passed between the two countries.