Archaeological research in the "Kalyata" area began in 2013, when the late antique fortress "Sitan Kale" was discovered. The first information about the fortress comes from the Byzantine chronicler Kedrin /late 11th - early 12th century AD/, who noted: "Sitan is a remarkable city..." - evidence that since that time it was a numerous settlement. According to its purpose, the fortress guarded the Razlog Valley, but at the same time it also served as a connection point with fortresses on the other side of Pirin - Melnik, St. Vrach /Sandanski/, etc. The fortified settlement is located at 1300m. above sea level on the territory of the "Pirin" National Park and is 3.5km. south of Bansko. It was built on a hill surrounded by almost sheer slopes, which are now overgrown with centuries-old trees. According to the observations made, it covers an area of ​​about 10 acres. Part of the eastern and northern walls with the gate of the citadel have been uncovered, which are built of processed limestone stones, bonded with mortar and are 1.80-2.00 m thick. A round tower has been built in the northeastern corner to guard the gate. Numerous fragments of household and construction ceramics, glass fragments, iron objects, arrows and spears, jewelry, etc. have been discovered. Based on the coins found so far, it can be safely stated that the settlement was inhabited during the period 3rd - 14th centuries AD. Under a project by the OPRD, part of the uncovered fortress wall has been restored and preserved. The fortified settlement can be reached along a well-designed tourist trail, secured with wooden railings. Signposts have been placed and rest areas have been set up. A large part of the discovered artifacts have been arranged in an archaeological collection and are exhibited in the Historical and Ethnographic Complex "Radonova House" in Bansko.