Built in 1784 by Nawab Asaf-ud-Daula as a famine relief project to provide employment, this massive complex is a masterpiece of Mughal engineering. Its central hall is one of the world’s largest vaulted chambers, notable for standing without any supporting beams or pillars. The complex includes the famous Bhul Bhulaiya, a dense three-dimensional labyrinth of nearly 1,000 interconnecting passages designed to support the building’s weight on marshy ground. Visitors can also explore the ornate Asafi Masjid and the Shahi Baoli, a grand stepwell. It serves as a spiritual hub for the Shia community, particularly during Muharram.