The Bara Imambara boasts one of the largest vaulted halls in the world – 50m long and 15m high. Flat on top, slightly arched inside, this imambara was built by Asaf-ud-daula in 1784 without the aid of a single iron or wooden beam; the roof was constructed using a technique known as kara dena, in which bricks are broken and angled to form an interlocking section and then covered with concrete – here several metres thick. The imambara is approached through what must have been an extravagant gate, now rather battered. Two successive courtyards lead from the gate to the imambara, on the left-hand side of which steps lead up to a fascinating labyrinth of chambers known as bhulbhulaiya – the “maze”.
Overlooking the Bara Imambara from the south, the Asfi Mosque is set on a two-tiered arcaded plinth with two lofty minarets. Even though it is inside the Bara Imambara compound, it is closed to non-Muslims, but anyone can check out its exterior, from the gardens adjoining it to the west.