Imambara, a unique archaeological monuments, was built by Asaf-ud-Daula in 1784 for famine relief, situated at the banks of river Gomti. Bara means big, and the term Imambara refers to a shrine dedicated for Azadari purpose by the Shiite Muslims, who gather there to observe Muharram. Among all the buildings of Lucknow it is the grandest. It includes the large Asfi mosque, the bhulbhulayah (the labyrinth), and bowli, a step well with running water. There are excellent views of Lucknow from the top of the Imambara.

Bara Imambara’, a historical edifice with such a marvelous architecture that even modern architects seem to be perplexed by its design. Its designer was Kifayat-ullah who is said to be a relative of the architect of the Taj Mahal. The structure shows the mixture of Rajput and Mughal architectures with Gothic influences. One of Asad-ud-Daulah's objectives in embarking on this grandiose project was to provide employment for people in the region. According to reports, the famine continued for over a decade and the construction of the building continued for this time. It is said that ordinary people used to work in the day building up the edifice, while noblemen and other elite were called at night to break down all the structure raised, as they were incapable of doing anything else, according to a chronicle of the period. This see-saw efforts continued till the famine period was over.It was a project that preceded a Keynesian like intervention for employment generation.

The Bara Imambara is, in fact, a great hall built at the end of a spectacular courtyard approached through two magnificent triple-arched gateways. The central hall of the Imambara is almost 50 meters in length and 16-meter wide. The ceiling of this columnless hall is more than 15-meter high. The hall is one of the largest of its kind in the world without any external support of wood, iron, or stone beams. The roof has been put together with interlocking bricks without using a beam or a girder. Hence, it is viewed as a unique achievement of architecture. The building, which consists of three huge halls, has an amazing maze of corridors hidden in between its walls that are about 20 feet thick. This dense, dark maze called the ‘bhul bhulaiya’ is to be explored only if you are strong-hearted. It is a network of more than 1000 labyrinthine passages, some of which have dead-ends, some end at precipitous drops while others lead to entrance or exit points. Help of a guide is recommended if one wants a tour of the secret labyrinth without getting lost.

Another intriguing structure at the Imambara is the five-storied baoli (step well), which belongs to the pre-Nawabi era. Called the Shahi-Hammam (royal bath), this baoli is connected with the river Gomti. Only the first two stories are above water, the rest being perennially under water.

There's a mosque with two tall minarets in the courtyard complex and to the right of this is a well which is said to have secret tunnels opening into. The Imambara is open from morning to 6pm.