Dubbed the Buzludzha Monument, after the mountain it was built on, the structure became the headquarters for the Bulgarian Communist party. Finished in 1981, it was only used for eight years before it was abandoned when the Iron Curtain fell.
While many in the government would like to restore the building - as it has become quite popular with tourists - the cost of doing so (an estimated $20 million) is too high a price for the state's coffers.
So, for the time being, the massive monument to a bygone era still stands, crumbling day by day.