The whole island of Astypalea is in fact a rich trove of archaeological treasure due to its geographical position and long history that has been traced back to the 3rd millennium BC . A collection of remarkable archaeological finds from the excavations is exhibited in the archaeological museum of Astypalea (at Pera Gialos). Archaeological sites and monuments are found dispersed around the island at Chora, Maltesana, Schinoda and Vathi.
There are also considerable byzantine influences which can be detected in the more than 400 churches and the domed chapels on the island. The byzantine era marks also the construction of the Castle of Agios Ioannis, situated on the southwestern coast of Astypalea, whose remains can be found up to today.