A monument in honor of the Bulgarian socialist movement. Construction began on 23 January 1974 under architect Georgi Stoilov, a former mayor of Sofia and co-founder of the Union of Architects in Bulgaria.
The monument is located at the point where the rebel leader Khadji Dimitar fought against the Turks in 1868. It was inaugurated in 1981 for the 1300th anniversary of the founding of the Bulgarian state.
The structure, which resembles a UFO in its structural form, has been in a steadily deteriorating condition since the collapse of the socialist state in 1989. The building exemplifies the futurist architecture common to many state-constructed communist buildings.