The UFO-like monument on the Buzludzha peak in Bulgaria, built by the country’s former communist regime to commemorate the events in 1891 when the socialists assembled secretly in the area to form an organised socialist movement, was opened in 1981, but abandoned after the fall of communism in Eastern Europe.

Today, the trespassing visitor can explore the site’s interior, finding traces of the mosaic frescoes that once artfully decorated the walls and investigating the debating chamber with the hammer and sickle symbol still blazoning the centerpiece of the ceiling.

Discover more photos of the decaying Buzludzha monument in our image search, or read Timothy Allen’s fantastic blog post of his visit to Buzludzha.

Photos from pavelgreen, _____ _____, Scouse_and_Jules, Digital Noise Photography, Nicolaiona, and Gonzlaught.