Sliven

The Cask is a cave located in the central part of the park on the north side of the famous rock Cask. Extremely natural phenomenon that is situated at about 1.5 m above the surrounding terrain in the rocks. Its form resembles a furnace with two sizes of 2 and 2 m height, cuts to up to two chimney. There is a fourth hole, resembling a window. It was declared a natural attraction.