This is the medieval orthodox church of Asenova krepost in Southern Bulgaria. The church was part of a larger fortress (Asen's Fortress) guarding one of the major mountain valleys leading into Bulgaria. Its architecture is unique as it is one of the few early medieval orthodox churches featuring an attached bell tower. Such towers are usually regarded a ‘western’ characteristic rare in the orthodox world, but in this case it was necessary to rise an alarm when invaders approaching the pass were spotted. Sound of bells would have been heard miles away along the mountain valley and alarm the inhabitants of the nearby city.