One of the most impressive and beautiful caves in Bulgaria is undoubtedly the cave located next to the village of Devetaki (Loveshko). It is also called the "Window" because of the seven differently sized cracks in the central hall ceiling.
The entrance to the cave is the largest on the Balkan Peninsula - 35 m wide and 30 m high. Inside, it expands to form a spacious hall whose height in places reaches 100 m. Two branches form 200 m from the entrance. - through the Water Gallery on the left, more than 2 km long, a small stream flows into the Osam River. The right sleeve is dry and warm, expanding inward, forming a hall with a small gallery and a circular room at the end, called the Altar.
Studies show that the Devetashka Cave has been inhabited throughout almost all historical epochs, with the earliest traces of human presence dating back to the middle of the Old Stone Age, as far back as 70 BC. In the recent past, Windows was used to store oil and food from the state reserve, and was later classified as a government military facility.
Apart from its archeological finds, the cave is rich in many inhabitants - over 12 species of protected amphibians, a dragon-mouse included in the Red Book, various members of the family of frogs, birds, turtles and mammals. Windows is one of the three most important breeding and hibernation refuges for bats in Europe, four of which are on the Red List of World Endangered Species.
Due to the breeding season of mammals inhabiting the Devetashka Cave, in June and July it is completely closed to visitors, and from November to March only the Water Gallery is closed.