Castle of Seyifler - Sakarya
To the south of the town of Ferizli, south of the Seyifler Village, the two towers in the western and northern part of the Kale ruins at the point where the Sakarya River is near the Çark Suyu are still standing. At a strategic point in the Byzantine period, on the Black Sea-Adapazarı road, it is possible to secure the safety of the bridges over the Çarksuyu and Sakarya River. It is a small castle in size. Seyifler castle where the impoundment water meets the Sakarya river. Harmantepe castle in the north of Harmantepe village, near the village of Poyrazlar, which is still completely destroyed, and the castles on the hills with Domuztepe and the castle in the east of the village of Kayal Mahmudiye. Çobankale holding the passage in the Geyve Strait, the Pahalar fortress in Pamukova and the Mekece fortresses are the Sakarya enclosure control towers of this genus.