Olto Castle, located in the center of Erzurum, specifically in the Olto region, was built in the 4th century BC, and it was used as a caravan station for a period of time during the Ottoman era, as it spread over an area of 3000 square meters. The castle, made of cut stone, was restored. During the Byzantine, Seljuk and Ottoman periods. The castle was characterized by the style of construction that was followed in it, where the high fortified walls designed specifically to repel enemy strikes, and inside, towers, strongholds and trenches, in addition to a chapel and a temple.