Kastro, Skiathos, Greece
Once the largest town on Skiathos, Kastro was established in the 14th century to protect the island from invasion. Situated on a peninsula on the north of the island, Kastro was a natural fortress offering panoramic views and having only one easily guarded path as it's only means of access. At its largest there were around 300 houses and 20 churches. Today only one church remains and the ruins of many others.