> I could give you a very simple example of cultural similarity across Europe. Religion. Pretty much the majority of European countries are Christians.

Christianity is kind of a big religion. The Americas (note the 's') could be said to be Christian. So I guess the Americas is one culture. At least Euorope also has the Orthodox branch. Not to mention the muslims in the Balkans.

> IMHO there are more similarities between European countries than between US States.

It genuinly blows my mind that some people actually believe this.