Zonguldak

Cehennemağzı Caverns (Karadeniz (Black Sea) Ereğli):
Cehennemağzı Caverns, which are also mentioned as "Caverns at Acheron - Akheron Valley" in the archeological sources of antic age, (Kehanet Caverns) is at the İnönü District, which is formerly named as Ayazma, of Ereğli, and is the mutual name of four caverns. Cehennemağzı Caverns, with being subjected to Greek Mythology, during the periods when Christianity was prohibited, is one of the worshipping places, thought to be used for secret worshipping.