Gölcük Hot Spring
Gölcük Hot Spring (Gölcük Yazlık Ilıcası) is a healing spring located at a distance of approximately 500 meters from Yaz Village of Gölcük District of Kocaeli. It is the only health related building that is located on the Ilıca Streambed and remains from the Byzantine period today. It is known that the Gölcük Hot Spring was first built in the Roman period and was used as a health center in the Byzantine and Ottoman periods.