Buzludzha Monument, Bulgaria
Perched in the Balkan Mountains, the Buzludzha Monument was built as a ceremonial headquarters for the Bulgarian Communist Party during the 1980s. When communism collapsed, state funding for maintenance disappeared and the massive concrete structure began to deteriorate. The main entrance is officially closed to the public, but the monument still draws photographers and urban explorers who appreciate its bold, brutalist architecture and the striking way nature and time are reclaiming its surfaces.