The settlement of Sklavonikolas is located 2.7 km away from Ioulis. A dirt road towards the monastery of Zoodochos Pigi (or Panagia Loutriani) starts from where building elements of ancient buildings are distinguished –a typical phenomenon in the old churches of Kea.
At a small distance from Sklavonikolas, following a short path, you will discover a part of the tower of Panachra, Hellenistic period, 4.5m high.
Better preserved is the tower of Agia Marina, a bit lower in the valley. It is five-storeyed and due to its reddish color it stands out from far away in the fully green landscape. It had a well and an underground tunnel connected to a spring at a distance of 200m (it was built for safety reasons as well since it offered a wayout in case of an attack).
According to some estimations, in Tzia there were 74 similar towers, which were built and inhabited from the 6th century BC onwards.
Next to the tower you will see the monastery of Agia Marina, abandoned for ages; however the celebration of the saint, on July 17, is still a cause for a big fesival.