Kástron is a charming and picturesque district located on the island of Sifnos in the South Aegean region of Greece. This historic area is known for its traditional Cycladic architecture, with whitewashed buildings, narrow cobblestone streets, and stunning views of the surrounding landscape. The district is centered around a medieval castle, which gives Kástron its name. The castle, built in the 15th century, is a prominent feature of the area and offers visitors a glimpse into the island's rich history. Surrounding the castle are a number of quaint shops, cafes, and tavernas, where visitors can sample delicious local cuisine and browse for handmade crafts and souvenirs.