The Acropolis of Kastro is located in the eastern part of the island, at the top of the village Kastro, the ancient capital of the island. It is one of the most remarkable archaeological sites, dating from the 6th cent. BC.
The wall that surrounded it, built with blocks of local marble, is visible today due to the excavations that have brought to light several parts of its perimeter with a height exceeding the 4 metres.
Some of the significant findings of the archaeological excavations found at the Acropolis are hosted at the Archaeological Museum in the heart of the village.