Historians sometimes call Easter Europe the 'The Zone of Political Change'.
This is usually done in the context of the Cold War between the United States and the Soviet Union. During this time, Western Europe was allied with the United States and was known for capitalistic economics and their NATO membership.
However, countries in Eastern Europe, such as Poland, Hungary etc were allied with the Soviet Union. They were known for their allegiance to the Communist cause.
By the 1980s and 1990s, there was local dissent rising in these countries against Soviet Union and it was increasingly referred to as the Zone of Political change.
