Devetàshka cave is a huge karst cave in Bulgaria, famous for its long term occupancy for human and other type biological populations during extensive historical periods. It is also home to nearly 30,000 bats. The inside view towards the main entrance and the first two big openings. The cave is also famous as Maarata or Oknata for its seven different-sized holes in the ceiling, through which sunlight penetrates and illuminates the central hall and part of its two fields.
Devetàshka cave is situated 15 km northeast of Lovech and about 2 km from the village of Devetaki. You can reach at cave by foot on a narrow path by the river, starting from the village of Devetaki, or access it directly from Road 301 via a 1,300 ft long dirt road and concrete bridge, constructed in 2011 for the filming of The Expendables 2. Devetàshka cave was exposed in the action movie The Expendables 2 filmed in 2011. The Supreme Administrative Court of Bulgaria declared that this filming was a breach of Bulgaria's environmental regulations. A countless bats were displaced from the cave, but at the late 2012, the majority of the bats had returned to the cave.
In the start of the 1950s, serious-minded explorations of the cave were held, concerning its transformation into a warehouse. In a study showed that the Devetàshka cave used to be inhabited with some interruptions during almost every historical era. The first traces of human presence date back to the middle of the Initial Stone Age before about 70,000 years BC. The Devetàshka cave is amongst the cave deposits with the richest cultural artifacts from the Neolithic. The cave entrance is 35 meters wide and 30 meters high. Approximately 40 meters after the entrance, the cave widens, forming a large hall with an area of 2,400 square meters. The height of the hall is 60 meters; even though at some places it reaches 100 meters.
About 200 meters of the entrance, the two fields break away from the hall. The left one is over two kilometers long, a little river runs along it, which passes through the central hall and flows into the Osam River. The right field is warm and dry. Its entrance is 2.5 meters high and 5.7 meters wide. The field widens after the entrance and forms a rectangular hall about 50 meters long and 10 to 15 meters wide. This field ends with a minor gallery with a round room, also known as the Altar. The cave was declared a natural landmark by order No RD 238/ 7 June 1996.