Among ravines and canyons in the Central part of the island of Thasos at the altitude of 450-500 m above sea level is one of the oldest settlements of the Castro (in Greek means "fortress"). The history of the settlement started in the beginning of the 15th century, when on a small mountain plateau, the Genoese built a powerful fortress. This place was chosen not accidentally. In the middle ages to protect themselves from the attacks of pirates, islanders for the most part built their fortified settlements in remote places away from the coast (usually high in the mountains). For a long time the settlement flourished and was well defended by its inhabitants.

By the end of the 19th century, Castro declined and completely empty. Some residents moved to the lowlands, where the conditions and fertile soil are most suitable for farming. Many settled in the new settlement "Limenaria" based German mining company Speidel, which began in these places the development of deposits of minerals, and some residents left the island in search of "a better life".

In the center Castro is a beautifully preserved Church of St. Athanasius is the oldest Church and an important historical monument of the island. According to an inscription it was built in 1804. Its construction involved virtually the entire population of Castro, and in the quality of building materials used parts destroyed by this time the castle of the Genoese. However, the ruins of a medieval fortress walls are partially preserved to our days.

For many years the settlement was abandoned. Only in recent years some of the houses have been restored and are now used in the summer and on weekends. Today, Castro is quite a famous landmark of the island. Here the atmosphere of a medieval settlement, and with the top of the plateau has splendid panoramic views. There is also a small cozy tavern. But Castro really comes to life during the celebration of St. Athanasius (January 18). At this time there are mass folk festivals with singing, dancing and traditional food which collect most of the residents of Thassos.