The imposing Venetian Castle of Astipalaia stands at a height of 100 metres over the town. It was built in the 13th century. It is also called the "Castle of Cuirini" from the name of the family which ruled the island from 1207 to 1522. The family's coat of arms still stands over its central gate. On the outside, one can see stone fortification walls with embrasures which were built to protect the island from pirates. Inside, among narrow labyrinthine passageways, were the houses of the members of the Cuirini family which were inhabited up until 1956. Of particular note are the beautiful old churches of Panagia Kastrou and Agios Georgios. From there, the view over Astipalaia is enchanting.
The Church of Panagia Portaitissa stands near the Castle of Astipalaia in "Rodia" (Pomegranate), which owes its name to the tree which used to be in its precinct. According to tradition, it was built by St Anthimos in the 18th century. On the outside, one can admire its dentelated dome, the many decorations which make it the most beautiful church on the island, and its imposing stone bell-tower.
Inside, there is a valuable wood-carved screen embellished with sheets of gold where the icon of the Virgin is kept. It is said to be a copy of the icon of the virgin of the Monastery of Ivira in Agio Oros.