Context: On 25 February 1991, the Warsaw Pact was declared disbanded at a meeting of defense and foreign ministers from remaining Pact countries meeting in Hungary. On 1 July 1991, in Prague, the Czechoslovak President Václav Havel formally ended the 1955 Warsaw Treaty Organization of Friendship, Cooperation, and Mutual Assistance and so disestablished the Warsaw Treaty after 36 years of military alliance with the USSR. In fact, the treaty was de facto disbanded in December 1989 during the violent revolution in Romania, which toppled the communist government, without military intervention form other member states. The USSR disestablished itself in December 1991.

Question: In which country did Warsaw Pact officials meet to dissolve the alliance?
Answer: Hungary

Question: In which year did Romania overthrow its communist government?
Answer: 1989

Question: For how many years did the Warsaw Pact formally exist?
Answer: 36

Question: What pact was disbanded on 15 February 1991?
Answer: Unanswerable

Question: In which country was the Warsaw Pact disbanded in 1981?
Answer: Unanswerable

Question: Which treaty was ended on 1 January 1991?
Answer: Unanswerable

Question: Which treaty was de facto disbanded during the 1989 violent revolution in Russia?
Answer: Unanswerable