The site is named after the river ("ποτάμι", pron. "potami" is the greek word for the river), that springs from the northeastern slopes of Mt.Kerkis, flowing into the sea. The coexistence of the luxuriant vegetation, the small lakes and waterfalls of the river, creates a unique panorama. The presence of three-almost contemporary-monuments, in close distance between them, attests to the florescence of a Byzantine and Post-Byzantine settlement in the area, which has not been fully explored yet. The first monument to the left of the path that leads to the river, also visible from the main road, is the Church of Agios Nikolaos (St. Nicolas), partially preserved today. The path, after circa 150 m., leads to the Church of the Saviour's Transfiguration, which is built on the east bank of the river. A short, uphill path beginning from the back side of the church leads to the Castle, a small fortress constructed on the plateau of a rocky outcrop of the mountain. The three monuments, dated between the 11th and 14th centuries A.D., form an indivisible unit, coexisting for centuries with the savage and captivating at the same time landscape of the site.
Evangelia Mavrikou