Location: Zonguldak, Catalagzi District
It is situated in Cumayani quarter at 3 km. distance from Çatalagzi district of Zonguldak province.
Properties: It forms the outlet of Kizilelma – Cumayani underground water system. It is opened to outside with many inlets. The hall is reached through a active gallery of 100 meters from the lower inlet or by walking for 75 meters from the upper fossil dry inlet. The hall begins with a travertine offering an extraordinary beauty and functioning as a bridge on the underground creek. The base of the hall, which has a height of 60 meters and a length of 70 meters, is covered with a thick sea layer and ends with a siphon. Upon going in the direction of water entrance to the left of the travertine, the siphon is reached in the direction of Kizilelma Cave. A boat is necessary in this gallery. As flood occurs in the rainy periods or at the times of a sudden rain, there is mortal danger.