On the northwest side of Keskin, on a hillside, there is a cave whose entrance looks small. Sulu Cave differs from the purely natural formations that come to mind when we say cave.

On the northwest side of Keskin, on a hillside, there is a cave whose entrance looks small. Sulu Cave differs from the purely natural formations that come to mind when we say cave. Part of it is the work of water and rock, and part is the work of human hands. Our Sulu Cave place page explains the practical side of a visit. This article looks at the rock structure of the cave, its three levels, its use in antiquity and how it can be read today.

Location and surroundings

According to the inventory record of the Culture Portal, the cave lies in the Keskin district, at the locality called Arzu Bayırı in Altıntaş Neighbourhood. It sits on the upper slope, facing southwest, of Karpuzbayırı Hill, part of a north-south ridge northwest of Keskin. The hill is given as 1191 metres high, and the point where the cave lies as 1180 metres. The record places the cave about 1 kilometre northwest of the Keskin town centre and 500 metres east of the Kırıkkale-Kayseri highway.

The Kırıkkale Governorship repeats the same location. In the records the cave also appears under the name Underground City. These two names mean the same place. The Ministry of National Education's out-of-school learning page gives the neighbourhood name as Gündoğdu. Because the sources differ on the neighbourhood, the most reliable description is about 1 kilometre northwest of the town centre.

Scientific study and the need for a map

According to the record in the Culture Portal, a report prepared by the experts of the Museum Directorate stated that the area called the Underground City needed a more comprehensive study than a preliminary survey. Cave researchers, that is speleologists, were to examine the area and an underground map was to be produced. This request was passed through the relevant general directorate for protection to the General Directorate of Mineral Research and Exploration (MTA). The 1996 examination by MTA is the result of this process. The record also says that opening the cave to tourism was considered appropriate under the scientific advice of the Museum Directorate or of the archaeology departments of universities. In other words, the cave is a protected area handled with the idea of scientific supervision, not casually.

A semi-natural, semi-artificial cave

Two words are the key to understanding the cave. According to the Culture Portal, the General Directorate of Mineral Research and Exploration (MTA), through its Geological Studies Department, examined the site in June 1996. The result showed that Sulu Cave is a horizontally developed fossil cave, half natural and half artificial, with the character of a sinkhole. The entrance section and the pool hall are the natural parts. The urn gallery and the lower mine gallery are artificial.

The first concept in this description is the fossil cave. A fossil cave is one where the water that formed it no longer flows at that level. The second concept is the sinkhole, a collapse or opening where water goes underground. According to the Kırıkkale Tourism and Promotion Portal, the entrance opened within marble and the pool hall are the natural section and belong to the Pliocene relief period. The natural core of the cave is thus presented as the product of a very old geological age.

Rock types and temperature

Different rocks are seen in different parts of the cave. The portal and the Ministry page state that one part contains marble, and other parts contain mudstone and sandstone. This variety is noticeable to the eye, since rock colours and textures change between the halls. The difference between the natural section opened in marble and the artificial galleries cut in softer rock also tells of the cave's two separate origins.

The portal gives the average humidity as 85 percent and the temperature as 18 degrees. The Ministry page also points to the constant temperature and high humidity of the cave. These values describe an interior environment largely independent of the season outside. Even so, knowing that the setting is cool and damp decides what you should bring. A light extra layer and non-slip shoes are enough preparation.

Three levels, three galleries

The cave, 285 metres long in total, consists of three connected levels. The three galleries are called, in order, the pool hall, the urn gallery and the lower mine gallery. According to the portal, the deepest point is 25 metres. The ceiling height varies between 1 and 4 metres. The MTA report in the Culture Portal adds that the thickness of the rock covering the ceiling ranges from 10 to 18 metres.

There is an important distinction. The whole 285 metres cannot be walked. Both the Kırıkkale Tourism Portal and the Ministry page state that a section of about 115 metres, which covers the pool area where water gathers between the rocks, is open to tourism. The Ministry's visiting notes particularly stress that visitors should not leave this tourist section. The rest of the cave exists only on the map.

Traces of mining

The word gallery comes from underground mining. According to the sources, the artificial parts of the cave were used as a mining gallery in antiquity. The Kırıkkale Tourism Portal writes that ore was extracted until recently in the urn gallery to the east of the natural section and in the lower gallery to the southeast. It explains that a large part of the cave was opened as a mine and that the three-level artificial galleries resulted from extraction.

I give no detail on the kind of ore, because the official sources say only mining gallery. This caution is a useful viewpoint for the visitor too. Noticing, while you look at walls and ceiling, that the surface was opened by human hands suggests that this place is a workplace as much as a natural wonder. Compare the rough, flowing shapes of the natural halls with the more regular surfaces of the artificial galleries.

Ancient water pools

According to the portal, pools up to 2 metres deep were built in antiquity to collect rainwater that ran in during wet periods. This information is a clue that also helps explain the cave's name. The pool hall is the section where the cave shows both natural and human-managed water. Do not enter the pools and do not touch them. The Ministry's visiting notes also ask that visitors stay out of the water.

There is one more piece of information about the pool hall. Both the Kırıkkale Tourism Portal and the Ministry page write that this hall is thought to have been used in the Early Christian period as a temporary shelter and settlement. This is an assessment of the cave's historical use and is not presented as firm proof.

Protection and opening to visitors

The record in the Culture Portal shows that the cave was registered by a decision dated 5 February 1996. The same record also says that MTA prepared an architectural and electrification project. The inventory text in the portal dates from 2013 and says that opening to tourism was foreseen. The Kırıkkale Tourism Portal, however, says that the Ministry of Culture and Tourism opened the cave to visitors in 2019 and that it serves with the status of an archaeological site attached to the Museum of Anatolian Civilizations. For the current situation, the portal and the Ministry page should be taken as the basis.

Only the Kırıkkale Tourism Portal mentions a university study on health. In this article I carry no claim about the cave's effect on health. This place should be treated as a stop for geology and history.

Practical notes for the visit

Days and hours may change. Before your visit, check the information on the Ministry's out-of-school learning page and with the Kırıkkale Provincial Directorate of Culture and Tourism. The Ministry's visiting notes say that the floor may be slippery and that there are stairs, narrow passages and low ceilings. Wear closed shoes with non-slip soles for this reason. Watch the low ceilings and, if possible, use a protective helmet.

Inside the cave, do not touch natural formations, do not enter the water, keep quiet and do not damage the surroundings. If you will take photographs, remember that humidity may fog the lens. Walking in small groups is better for both safety and visibility. Because it is close to the Keskin centre, it can be planned on the same route with the Çeşnigir Bridge and the Kırıkkale Nur Mosque.

In short, Sulu Cave is the story of a cave opened by water that human hands turned into a mine. With its natural hall, galleries and ancient pools, it offers a short but informative walk underground.

Sources

Culture Portal, Sulu Mağara, https://www.kulturportali.gov.tr/turkiye/kirikkale/kulturenvanteri/sulu-magara694295
Ministry of National Education, Out-of-School Learning Environments, Sulu Mağara, https://okuldisiogrenme.eba.gov.tr/place-detail/sulu-magara-1797
Kırıkkale Tourism and Promotion Portal, Sulu Mağara, https://www.kirikkale.com.tr/mekan/sulu-magara
Kırıkkale Governorship, Underground City and Nature Park page, https://www.kirikkale.gov.tr/yer-alti-sehri-tabiat-parki

Sulu Cave and the Mining Gallery Inside the Rock