Devetashka cave, Bulgaria

Devetàshka cave (the name in Bulgarian: Деветашката пещера) is a huge karst cave 7 kilometers from Letnitsa and 15 km northeast of Lovech, near the village of Devetaki on the east bank of the river Osam, in Bulgaria. It is known for its long term occupancy for human and other type biological populations during extensive historical periods, and also home to nearly 30,000 bats.

Devetashka cave is located 15 km (9.3 mi) northeast of Lovech and approximately 2 km (1.2 mi) from the village of Devetaki. To reach the cave one can walk along a narrow path by the river, starting from the village of Devetaki, or access it directly from Road 301 via a 400 m (1,300 ft)-long dirt road and concrete bridge.

In addition to archaeological findings, the cave is known for the diversity of residents. Because the breeding season of mammals inhabiting the cave spans from June through end of July, it is entirely closed to visitors. There live twelve species of protected amphibians and reptiles, including aesculapian snakes, triturus, tree frogs, Hermann's tortoises, eighty-two bird species found in the area (thirteen of which are included in the Red Book), thirty-four species of mammals (four of which are included in the Red Book) and fifteen species of bats.

The cave's galleries and entrances are used by bats and crag martins.

Photo Source: Collected from Internet