International Day against Nuclear Tests (established December 2, 2009 by UN General Assembly Resolution 64/35).
On this date in Bulgarian history:
866: Embassy of Bulgarian Tsar Boris I arrives in Rome, bringing 106 questions to Pope Nicholas I about the teaching and discipline of the Christian church (answered in “Responsa Nicolai ad Consulta Bulgarorum”, written by Anastasius the Librarian).
1954: Soda Ash Plant at Devnya (Northeastern Bulgaria) goes into operation (sold to Belgian company Solvay and renamed Solvay Sodi in 1997).
1990: Bulgaria establishes regular diplomatic relations with NATO.