Devetashka cave is one of the biggest caves in Bulgaria but it is most famous for its amazing history. It is also currently home to nearly 30,000 bats. Devetashka cave is located 18 kilometers northeast of Lovech and 2 kilometers away from the village of Devetaki. The cave is also known 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. 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 long dirt road and an ugly concrete bridge which was constructed in 2011 for the filming of The Expendables 2. In the beginning of the 1950s, serious explorations of the cave were held, concerning its transformation into a warehouse. The studies showed that the Devetashka cave used to be inhabited (with some interruptions) during almost every historical era. The earliest traces of human presence date back to the middle of the Early Stone Age before about 70,000 years BC. The Devetashka cave is among the cave deposits with the richest cultural artifacts from the Neolithic (6th millennium - 4t h millennium BC).