Bulgaria and Eastern Rumelia declared their unification on September 6, 1885. Unfortunately, no one outside of Bulgaria—neither the Western Powers nor the Ottoman Empire, of which Rumelia had been a part—recognized the union.
The declaration precipitated the Serbo-Bulgarian War in which Bulgaria defended its borders, and Bulgarians still celebrate September 6 as the anniversary of its unification.
This year (2009) most events celebrating Unification Day have been canceled, due to a tragic boating accident on Saturday which killed 15 Bulgarians. The boat Ilinden sank in Lake Ohrid, Macedonia. An investigation as the cause of the sinking is currently underway.
Instead, the President has declared Monday, September 7 a National Day of Mourning.
Memorial services for the victims were held at Plovdiv Cathedral, and were attended by the President and Speaker of Parliament.
During the mass, the Plovdiv Metropolitan, Nikolay, hinted that God had punished Bulgarians over their many sins including celebrating and partying too much on August 29 (the day of the concert of pop diva Madonna in Sofia) instead of mourning for St. John the Baptist.
Bulgarians will still lay a wreath at the Unification Monument in Plovdiv, though there will be no fireworks.