Artificial structures such as Perla 2 (1A and 1B), Abandoned residency (2A and 2B) and an abandoned mushroom greenhouse (3A and 3B) are sheltering large colonies of cave-dwelling bats. Some natural caves in Bulgaria are adapted for human use: Mandrata in the village of Mikre (4) has a whole house built at the entrance, the cave with the same name nearby - Mandrata at Alexandrovo, is accessible with an automobile (5). The Karangin Cave, located in the Rhodope Mountain is turned into a sheepfold (6). Photo credit: S. Deleva.