Collective Security Treaty Organization (Carpe Diem)

The Collective Security Treaty Organization (: Организация Договора о коллективной безопасности, Organizatsiyz Dogovora o kollektivnoy bezopacnocti), often abbreviated as the CSTO (ОДКБ, ODKB), is an intergovernmental military alliance between Bulgaria, Czechoslovakia, Hungary, Mongolia Poland, Romania, the Soviet Union, and Yugoslavia. The organization was established in 1991 following the mass reformation of the Soviet Union and the Eastern bloc countries.

Member states

 * Flag of Bulgaria.svg Bulgaria
 * Flag_of_Czechoslovakia.svg Czechoslovakia
 * Flag of Hungary.svg Hungary
 * Flag of Mongolia.svg Mongolia
 * Flag of Poland.svg Poland
 * Flag_of_Romania.svg Romania
 * Flag of the Russian Federation (1997 proporsal).svg Soviet Union
 * Flag of Serbia and Montenegro.svg Yugoslavia