Isn't that between 4 states though? Rather than 4 countries lol still super cool though

Which is on an indian reservation, and requires an entrance fee to go look at it.

When I was in Germany in 2022, I traveled freely around Germany, France, Belgium, Switzerland, and Czechia. I only got asked for my Passport in Switzerland, and then at the airports. Otherwise, no, you'd just be driving or on a train and the signs would change to French suddenly.

I loved it. I wish we fucking would relax our shit in the US. It was hella neat.

Do you have border control between states? It's basically the same thing with schengen. No control between countries on the "inside", but rigorous control to get in.

Why would there be? All three countries are in the Schengen area.