The Great Castle of Chora or New Castle is in its current form a Frankish building in Kalymnos. It is located in Chora of Kalymnos, the old capital of the island and opposite the nearby Castle of Chrysocheria. It is a castle city since it surrounded a medieval settlement.
It is located at the foot of the hill of Profitis Ilias at an altitude of 255 meters and occupies an area of 30,450 square meters. It had strong walls and had only one gate as it was accessible only from the south side which was higher than the ground and went up or down with a chain depending on what was needed. Its walls are preserved in height up to seven meters and thickness 1.50.
The castle was first built in the 11th century by the Byzantines to counter the invasions of the Ottoman pirate Jaha. It suffered great damage from an earthquake in 1492, to be renovated then within three years in its current form by the Knights of St. John of Rhodes, where in the meantime Kalymnos belonged.
The settlement of the castle is estimated at 1,200 to 1,500 inhabitants, there are ruins of an olive mill, water tanks, houses and 10 churches. The castle was inhabited even during the Turkish occupation and in 1912 where it was abandoned by its last inhabitants. Gradually, since the 17th century, there has been a relocation of inhabitants to Chora and Pothia.