Devetàshka cave (Bulgarian: Деветашката пещера) is a large karst cave around 7 km (4.3 mi) east of Letnitsa and 15 km (9.3 mi) northeast of Lovech, near the village of Devetaki on the east bank of the river Osam, in Bulgaria. The site has been continuously occupied by Paleo humans for tens of thousands of years, served as a shelter for various faunal species during extensive periods and is now home to nearly 30,000 bats.
Source: Wikipedia
