East of the river Axios, in the center of the plain of Kilkis, the megalith of Chorigio is the most characteristic natural feature in the relief of the area. The geological formation with rocks, which circle the top of the hill like a wreath, creates a natural castle, which people had used to create settlements around it from prehistoric times, as evidenced by the findings at the site.
The hill of Chorigio is also known as "Kalambak" ("fortress on the rock" in Turkish) or "Lazaritsa" / "Lazarina", from the local tradition with the girls of the surrounding villages who announced the resurrection of Lazarus dressed in traditional costumes, or simply as "Castle". Due to its natural fortification, but also as the only hill in the plain with the possibility of observation in a long radius, it was used as an observatory and headquarters of military operations, especially during the First World War.
It is located north of the Provincial Road that connects Kilkis with Axioupolis, at 1.5 km from the homonymous settlement, and is characterized as a natural monument.