The Monument to the Unknown Soldier features an eternal flame, turf from Stara Zagora and Shipka Pass, sites of two of the most important battles of the Russo-Turkish War of Liberation (the Battle of Stara Zagora and the Battle of Shipka Pass), a sculpture of a lion (a national symbol of Bulgaria) by the noted sculptor Andrey Nikolov, as well as a stone inscription of a stanza (part of The New Graveyard Above Slivnitsa 1885 poem) by the national writer Ivan Vazov:
БЪЛГАРИЙО, ЗА ТЕБЕ ТЕ УМРЯХА,
O BULGARIA, FOR YOU THEY DIED,
After end of the First World War, a group of Bulgarians proposed building the monument. However, strong opposition to the building of this monument arose. Some Bulgarian intellectuals argued that a monument of an unknown soldier is unacceptable because this would mean that we have forgetten the names of our soldiers. "Not a single soldier shall be forgotten who gave his life in this war and in all other wars for the freedom of Bulgaria!".
The monument was designed but was not displayed because of the above mentioned arguments. The lion itself was considered an abuse for a long time because it was sitting. The pose was considered a metaphor of surrender to the national ideas. For more than fifty years the statue and the idea of the monument stayed frozen until finally it was officially opened in 1981 for the 1300 years' celebration of the founding of Danube Bulgaria.