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Photo: Samudra013, CC BY-SA 4.0 via Wikimedia Commons
The Topekhana was to the south-east of the Katra Masjid, and there still is a huge cannon named Jahan Kosha (Destroyer of the World), which is said to have been brought from Dhaka when Mushid Quli Khan shifted his capital.
The Jahan Kosha Cannon, also known as the Great Gun, is placed in the Topekhana, 400 meters to the south east of the Katra Mosque, in the town of Murshidabad, West Bengal, India. Topekhana was the Nawabs' artillery park and the entrance gate of the old capital of Bengal, Bihar and Orissa, the city of Jahangir Nagar. It is protected on the east by the Gobra Nala, locally known as the Katra Jheel. Before being placed at its current location, it lay on a carriage with wheels and was surrounded by the roots of a Peepal tree. The growth of the tree roots gradually lifted the gun four feet above the ground. The wheels of the gun carriage have disappeared, but the iron-work of the carriage and the trunions are still visible. The cannon is made of ashtadhatu or 8 metals, namely silver, gold, lead, copper, zinc, tin, iron and mercury.
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Built by Nawab Murshid Quli Khan (reign: 1717 -27) in 1723 AD. It is damaged but well maintained. The main mosque had five domes, out of which two collapsed in the earthquake of 1897. Many of the buildings in and around the mosque also collapsed during the earthquake. 2000 people could offer prayers in the mosque at the same time.
An abandoned mosque, with only two of its five domes being completed. Sarfaraz Khan (reign: 1739-40) started its construction in 1740, but after his defeat and death, the construction was abandoned and ever since then the mosque lies in that same state. It is 135 feet long and 38 feet broad. The centre of the western wall houses a triple mihrab.
A park complete with toy train rides and a children's activity centre.
The triple arched gate is topped with a nahabatkhana. The arches are high enough to let elephant pass. It was built by Nawab Shuja Uddin Khan who succeeded Murshid Quli Khan.
The Chawk Mosque was built in 1767 by Munni Begum wife of Mir Jafar. The mosque has five domes and approached through an entrance flanked with minerates
South Gate
The southern entrance of Quila Nizamat. The single arch entrance is surmounted by a Nawbat Khana, where royal instruments were played. The entrance is large & high enough for an elephant to pass with a howdah on its back. It was built by Nawab Ahmad Ali Khan. The Ghari Ghanta just north of the Dakshin Darja consists of a bell on top of a bastion.