Belgrade Liberation Day is observed in Serbia every October 20, commemorating the liberation of Belgrade during World War II. This event marks the anniversary of the city's liberation from Nazi occupation, which began in 1941 and lasted over three years until Belgrade was freed on October 20, 1944, through the efforts of the Soviet Red Army, the National Liberation Army and Partisan Detachments of Yugoslavia, and the Bulgarian People's Army. The military operation responsible for this liberation is known as the Belgrade Strategic Offensive Operation. Although it is not a public holiday, the day is marked with military parades and various events across the country. The liberation of Belgrade was significant, as it represented the first step towards the liberation of the rest of Yugoslavia, making its anniversary an important observance in Serbian history.