Tannu Tuva stamps
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Tannu Tuva was an autonomous region in central Asia between Russia and Mongolia, which in 1921, under Russian instigation, became the Tuvan People's Republic. A treaty between the Soviet Union and the Mongolian People's Republic in 1926 affirmed the country’s independence, although no other countries formally recognized it. In 1944, it was annexed to the Soviet Union as part of the Tuvan Autonomous Oblast and in 1961 became the Tuva Autonomous Soviet Socialist Republic. Its successor since 1992, the Tuvan Republic, is a member of the Russian Federation.
Best website related:
Tannu Tuva and its Philatelic History