The Gyzi Castle of Mykonos Cyclades: The castle of Gyzi lies on a hill above the village of Ano Mera, in the center of Mykonos island. It dates from the 13th century and only some ruins of it remain today. It was built during the rule of the Gyzi family, a noble Venetian family that was ruling the Cyclades in the Medieval times, to protect the island from pirates and enemy attacks.
This area also hosts the ruins of the ancient city of Mykonos and you will find remains of a prehistoric market, an ancient cemetery and some ruins of an even older wall fortification. Near Gizi Castle, you will find the church of the Holy Saviour, dating from the 18th century. This hill gives an awesome view to the northern side of the island.
https://www.greeka.com/cyclades/mykonos/sightseeing/gyzi-castle/