Gulbarga Fort in near the town of Gulbarga in Karnataka. It was built during the 14th century by Bahmani Kings. Later, additions were made in Persian architecture. The fort also has the world largest cannon in the Gulbarga fort made out of alloy. It measures 29 feet in length, 7.6 feet in circumference, 2 feet dia and 7 inch thickness.
There is also a tomb of Sufi saint-Syed Mohammad Gesu Daraz, popularly known as Khwaja Bande Nawaz here. The major part of the fort is in ruins. Those who are interested in history can visit the fort. If you are nearby Gulbarga town, do not miss the fort. The entry is free, so one can visit it in the evening.