Late antique and medieval fortress Momina kula is located on the island hill of the same name, 2.04 km southwest as the crow flies from the centre of Gotse Delchev. The fortress has an irregular shape with an area of over 10 hectares. A massive wall runs along the periphery of the hill. The southern wall, over 1 m wide, is preserved at a height of up to 6 m. Its faces are made of small blocks. The wall is also well preserved in the north-west corner. To the south there are remains of earlier constructions – a circular structure built of rubble.