Answer:
Poland
Step-by-step explanation:
On 4 June 1989, the trade union Solidarity won an overwhelming victory in a partially free election in Poland, leading to the peaceful fall of Communism in that country in the summer of 1989.
Also in June 1989, Hungary began dismantling its section of the physical Iron Curtain.
On 27 October 1991, the first entirely free Polish parliamentary elections since the 1920s took place.
This completed Poland's transition from a communist party rule to a Western-style liberal democratic political system.
The last post-Soviet troops left Poland on 18 September 1993.