Sulu Cave Sulu Cave can be found in the Arzu Bayırı area of the Keskin district in Kırıkkale. It is a partially man-made and partially natural sinkhole type of fossil cave that has a horizontal structure. The cave is made up of three interconnecting floors, which are part of the Pliocene relief system. The cave has a total length of 285 meters, with lead mining operations carried out in the artificially constructed galleries on the three floors. The narrow passageways connecting the natural and artificial sections of the cave are covered by stone walls that were built during the Early Christian Period. Sulu Cave is situated in the vadose zone hydrologically, which means that it is entirely dry, except for water droplets that fall from the ceiling during rainy periods. In ancient times, pools with a depth of 2 meters were constructed to collect the water from the dripping ceiling. The cave has a hot and dry climate. The Kırıkkale Governor's Office and the Special Provincial Administration have made the cave accessible for visitors by constructing necessary facilities and landscaping the area.