Buzludzha
This monumental structure standing on the top of a mountain in central Bulgaria is known as Buzludzha. It commemorates the golden days of the Bulgarian Communist Party. In the years following its completion in 1981 it was used as a gathering location for political meetings but since the fall of communism in 1989 Buzludzha has been falling into decay. As of today, it is closed to the public and several preservation projects have been initiated to preserve the historical site.
Devetashka
Scattered all around the country caves hide in the landscape. This one, the Devetashka cave is one of the most spacious featuring large openings in the ceiling that allow daylight to lighten the vast interior. The cave has been occupied by Paleo humans for tens of thousands of years, served as a shelter for various faunal species during extensive periods, and today it is home to nearly 30,000 bats. Today the cave is open to the public but previously it was used by the military as a storage site.