Megalo Kastro (also known as the Castle of Chora) on the Greek island of Kalymnos. Megalo Kastro was actually the ancient Chora (main town) of Kalymnos: a walled town rather than a castle, it was located on an isolated hill which was a fortified location itself. In the 11th century the walled town was turned into a fortress by Byzantines. When in 1310 Kalymnos came under the sovereignty of the Knights of Saint John, Megalo Kastro was repaired and extended, still being the residential centre of the island. After the fall of Constantinople in 1453, the Knights Hospitaller, with the support of Pope Paul II strengthened all their fortresses in Dodecanese, with Megalo Kastro not being an exception: from the coats of arms embedded in the walls it is possible to identify that the fortifications were improved and were modernized in the early 16th century, shortly before the ultimate fall of the Sovereign State of the Order of St. John in Dodecanese. In 1523 the Knights left Dodecanese, after turning the islands over to the Ottomans, but Megalo Kastro was inhabited until the 18th century. Since then, it has been a ghost town for a very long period during which most of its buildings collapsed. In recent years the remaining churches and fortifications were included in a program of restoration.