Unification Day is a Bulgarian public holiday observed every September 6, commemorating the unification of the principality of Bulgaria and the Ottoman province of Eastern Rumelia in 1885. The day marks the successful capture of Plovdiv by armed rebels from the Bulgarian Secret Central Revolutionary Committee, led by Zahari Stoyanov, who overthrew the local governor and established a temporary government. Celebrations occur nationwide, with significant events in Plovdiv, including official ceremonies, memorial services in churches, firework displays, and a traditional memorial marathon. This holiday reflects the historical significance of the unification and the efforts of those who advocated for it.