Karstic landforms that developed in the limestones, with significant hydrogeological, geomorphological, and archaeological (speleological) interest. Scientific treasures are housed within the sinkholes and provoke interest in exploration. On the Astraka plateau, the limestone substratum, the high altitudes, and the climatic conditions contributed to the development of impressive caves and sinkholes, such as:
Η «Ewe», 408m deep, one of the world's largest vertical abysses, the «Chasm of the Epic», a stepped abyss, 451m deep, the «Bride's Hole», with a total depth of 340m, the «Gaillohole», 200m deep, «the Raven's Hole», 610m deep, and many others.