Perla 2

After the fall of the Bulgaria's communist regime in 1989, nature has begun to take back what would have been a major monument to the rule of dictator Todor Zhivkov. Just minutes from popular beaches on the Black Sea coast, near the city of Primorsko, is an isolated patch of forest where one can wander around the abandoned, never-finished grand residence Zhivkov had planned, known as Perla 2 (perla means "pearl"). (Not to be confused with Perla 1, another abandoned Zhivkov residence nearby.) 

The massive building today consists of a skeletal frame of raw reinforced concrete and arches of steel, with multiple wings and countless rooms that provide plenty of fodder for the imagination—just what kind of opulence would have been there, or which rooms the dictator planned to inhabit. The building also serves as an example of the brutalist architectural style.

Unfinished stairways lead to different areas, including ones that go to the flat roof. The terrace has begun to resemble a swamp, with water and even wetland plants, topped with a few trees. And last, for the brave and perhaps foolhardy, are the steps down to the basement. There resides a colony of hundreds, if not thousands, of bats, and who knows what else.