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This postcard commemorates 20 years of Belarusian stamps. Belarus used the postage stamps of the Soviet Union from 1917 to 1991. In 1991 Belarus became an independent nation and began its own postal administration in 1992. (Wikipedia)
Belpost has a very nice website in English, and I think you can find information on all their stamps there. Stamps are listed both chronologically and thematically. Architecture is the theme of the stamps on this postcard. The architecture stamps are on a page called Architectural Monuments. I didn't try to identify all of these stamps, but I did look up the two souvenir sheets in the center of the postcard: Mir Castle (2010) and Orthodox Churches (2012).
This is a post for Sunday Stamps at Viridian's Postcard Blog