Unification day in Bulgaria is always on September 6th each year and commemorates unification of eastern Rumelia and Bulgaria back in 1885.
People spend the day with family and friend relaxing and enjoying the time off. This day is a national holiday with most government and business offices closed.
The Treaty of Berlin back in 1878 separated southern Bulgaria from its newly formed state. The people of Bulgaria wanted to be reunited. Over seven year efforts were made to re-unite and finally after the Serbo-Bulgarian war in which the Bulgarians won unification was complete.