Markeli fortress
The medieval fortress of Markeli is located at the Hissar hill in East part of Stara Planina mountain, 7.5 km west of town of Karnobat. The castle was an important military center and has played a major role in the Bulgarian-Byzantine relationships. It was built probably during the Byzantine emperors Anastasius I and Justinian in order to guard the only road to Varbishki and Rishki Passes.
From 812 the castle is a Bulgarian possession and Khan Krum made it the largest Bulgarian stronghold in the south of Stara Planina mountain.
The total area of the citadel was 460 acres and the length of the walls - 530 m. The fortress was impregnable, and when it was under a siege it was supplied with water through specially constructed water facility connecting the city with the nearby river.
After archaeological excavations in Markeli fortress were discovered medieval basilica from VI century, Old Bulgarian Church from the X century, a Byzantine church from the XI century and many artifacts such as bronze coins from VI-XIII century, fragments of graphite drawings, ceramic mosaics and bronze medieval seals.
