Adıyaman Arsameia Ruins, A Summer Palace On The Shore Of Kahta Stream: Arsameia is the summer capital and administrative center of the Kingdom of Commagene, which gifted wonderful artifacts to the world heritage, was a junction point where the Commagene kings made an effort to synthesize East and West culture, reflecting the ideal of creating Greek-Persian culture.There is a cult inscription in Arsameia, which sheds light on the history of its age and is the longest Greek inscription in Anatolia. In the content of the inscription; establishment of the city, the laws of the Commagene Kingdom, the kingship lineage, the architectural structures and reliefs in the region, the religious structures and the things to be done during the ritual are mentioned. There is a stepped tunnel located just below the cult inscription and descending with a high incline, is 158.1 m long. The purpose of this tunnel is not fully understood.There are deity and king reliefs on the summer palace on the hill and the ceremonial road leading to the tomb of Mithridates Kallinikos. On these reliefs, gods and kings are depicted in dexiosis (handshaking). These are scenes from Antiochos I, Heracles, Mithridates Kallinikos and Persian culture.