The Anniversary of the Declaration of the Slovak Nation is observed in Slovakia every October 30. This memorial day commemorates the official joining of the Slovaks to Czechoslovakia, which occurred on October 30, 1918, when the Slovak nation issued a declaration in the city of Martin. The event marks the culmination of efforts by influential leaders such as Edvard Beneš, Tomáš Masaryk, and Milan Rastislav Štefánik, who worked towards the establishment of Czechoslovakia after World War I. The concept of Czechoslovakia was initially outlined in 1915, and a final agreement was signed in Pittsburgh on May 31, 1918. While Czechoslovakia declared its independence on October 28, 1918, it was not until the Slovak declaration that Slovakia officially joined the new state. This anniversary serves as a remembrance day in Slovakia, reflecting on the historical significance of the event.