[DrJaws]

If you go from Paris to Warsaw, you still won't need a passport, just a basic ID

Schengen area

travelling around Europe as European is not much more hassle than moving on the US from one state to the other.

[OkayPhysicist]

Huh, TIL. I had assumed that you needed a passport, they just didn't do border checks.

[ben_w]

In addition to the other answers, I'd like to add that the Schengen area, the EU, and the Eurozone are all technically separate, none is a subset of one of the others:

https://en.wikipedia.org/wiki/Template:Supranational_Europea...

https://en.wikipedia.org/wiki/Schengen_Area

https://en.wikipedia.org/wiki/European_Union

https://en.wikipedia.org/wiki/Eurozone

Ireland and Cyprus are in EU & Eurozone but not Schengen; Poland, Hungary (and more) are in EU & Schengen but not Eurozone; Switzerland is in Schengen but neither EU nor Eurozone; Montenegro and Kosovo are in the Eurozone but neither the EU nor Schengen.

[jauco]

In europe we have a kind of mini passport, called person id. Which only works in your own country and other shengen countries. It’s nearly the same cost as a passport (at least in my municipality)

You are required to have a passport (or id) with you (as in, that’s what the law says). Even in your own country. But in your own country a drivers license is usually also sufficient.

But in practice you will almost never be asked to show any of those. In your own country, nor abroad.