What are example of a open country?

Literally, it means a stretch of country that is reasonably flat and not densely forested. Often it is used to indicate that it is also not densely populated. If it is used for a whole nation, it means that people, goods and information can freely go in and out. Examples are: the Prairie, the Pampas, the Savannahs. Open nation-countries: the US, Denmark, Canada, and a lot of other Western democracies.