The Dah-Sheikh cave, which is 135 million years old, is located in the heart of the Dena mountains near a village in Kohgiluyeh and Boyer-Ahmad province. It is one of the 600 discovered caves in Iran, ranking second in terms of depth and size. The cave is estimated to be 6 kilometres deep. As the cave is so large, parts of it have not been explored yet.
The cave dates back to the second geological era and is a completely natural lime cave. Rain and snowfall have created holes in the cave over the years. That has caused water to flow out of the holes, creating wonderful icicles and passageways.
There are no paintings on the walls, which indicates this place has remained intact for centuries. What is strange about this cave is that the weather inside is warm in winter and cold in summer. The mysterious warmth inside the cave during cold season is a puzzle not solved yet.
The entrance to the cave lies 1,670 metres above the sea level and is so small and dark that one needs to pass through it in a squatting position for five to six metres. The cave is up to seven metres high in some parts. One can find different types of beautiful lime icicles in its passageways.
The Dah-Sheikh cave is one of the caves where remains of humans, animals and clayware have been unearthed in archaelogocial excavations. This shows humans who existed during the emergence of Islam used to live in the cave.
The clayware items and bones discovered in the cave date back 135 million years old, which shows human beings chose to live in that colossal cave.
Archaeological studies show the discovered clayware dates back to the Achaemenid and Sassanid eras.
In some passageways of the cave, one may find insects like spiders, centipedes, cockroaches and beetles as well as birds and other animals such as bats, rats and different types of arthropods.