In Coastal Astros, on the hill above the cove that the locals are referring to as nisi (island) is located a castle of the 13th century AD. It was the fortress and the residency of the Venetian Governor and was used as such and in Ottoman Empire. It has a quadrangular ichnography and maintains a large part of the fortress' compound and one of the towers.  The two exterior gates of the castle are preserved till today. Inside the castle, three pre-revolutionary residencies, which were built by three wealthy siblings in order to stage the local revolution, have been preserved, too.