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Canon HF10 Orlova Chuka Cave is one of the longest caves in Bulgaria. The entrance opens to the romantic valley of the Cherni Lom river, 40m above the river. It was formed by ground water around the Pliocene/Quaternary boundary, when the valley floor was 40m higher at the level of the cave.
The cave contains several archaeological remains. The upper cave sediments contained remains of the Thracians, which lived here during the Bronze Age and the time of the Romans. Older layers brought Palaeolithic finds like flint arrowheads and the bones of cave bear and deer.
Orlova Čuka is home to a huge bat colony, and during their maternity phase in May or June the visitors are not allowed in this part of the cave for about a month. Biologists from the Bulgarian Academy of Sciences continually supervice the bats. They mount cameras around the colony and so visitor can see how bats are born in the nearby hut "Edelweiss". 29 species of bats are known in Europe, 25 of them are found here.
The karst area around the river Russenski Lom in northeastern Bulgaria is full of caves. 56 caves were discovered and mapped so far. The area is called Lomovete, which is also the name of the narrow gorges. The rivers are called Rusenski Lom with its tributaries Cherni Lom, Beli Lom and Malki Lom.
