In order to keep track of these diverse groups, anthropologists and geographers have divided them into “culture areas,” or rough groupings of contiguous peoples who shared similar habitats and characteristics.
Answer:
I would say National Capitals. There are very few, if not any communist countries or cities in Europe. Agricultural regions usually have less population density. Landlocked cities do make some sense, although I don't think it is Landlocked.
Responsibility for the end of communism in Europe would be is the Revolution of 1989. Also, president Gorbachev sent soviet troops to their rescue at this time. Hope this helps!